“Congratulations, you are pregnant!” – doctors used to say these words more often; with the advent of express pregnancy tests, they can be read in the instructions for the test. In any case, most women call pregnancy and motherhood the most amazing time in their lives.

It is not without reason that they say that a pregnant woman seems to glow from within; she is especially beautiful and attractive during this period. Of course it's a miracle! The expression is a little hackneyed, but, in fact, when a new life arises from a lump of mucus during 40 weeks of pregnancy, there is no other way to call it

Pregnancy is a physiological state of the body. The changes that are taking place are programmed by Mother Nature. These changes are so significant that because of them, a woman’s whole life switches to a new rhythm: about 80% of women feel nausea, especially in the morning; the perception of odors is heightened, some of them cause unpleasant sensations, including severe nausea and vomiting; the usual diet may change - your favorite food may cause disgust, and dishes that were previously on the list of hated foods may appear in first place; increased fatigue; an incomprehensible drowsiness is annoying; frequent urge to urinate; sudden changes in mood; tearfulness.

How pregnancy begins and develops

Fertilization

Each time in the middle of the menstrual cycle, one, rarely several, follicle matures in the ovaries. The follicle contains an egg. The moment the egg is released from the follicle is called ovulation. After release, the egg is picked up by the fallopian tubes and slowly moves towards the uterine cavity. If during this short (3-6 days) period of time a woman has sexual intercourse without means of preventing pregnancy, pregnancy may occur. The egg produces special substances that signal the sperm about where it is. If the “rendezvous” takes place, fertilization occurs. Pregnancy begins.

Fertilization occurs in the fallopian tubes, even before the egg enters the uterine cavity. After the fusion of the egg and sperm, a zygote is formed, from which the growth of the embryo begins.

What happens and what does the embryo look like? How will the size of the embryo change over the weeks? What changes will occur during the process of growth and development? What do photos of an embryo look like by week? Ultrasound is used to observe how the embryo develops over weeks and months.

Embryo 1 week

The zygote is still in the fallopian tube on its way to the uterus. The fallopian tubes are lined with villi, which move the egg toward the uterus. If the zygote does not enter the uterus within a certain time, it may attach to the wall of the fallopian tube. In this case, they talk about ectopic pregnancy - a condition dangerous to health and life.

During fertilization, the sperm brings in its 23 chromosomes, which combine with the 23 chromosomes in the egg. Moreover, depending on whether the sperm contains an X or Y chromosome, the gender of the unborn child depends.

After fertilization and the formation of a zygote, about 30 hours pass. The fertilized egg begins to divide. This process is called crushing, since with a slight increase in volume, the number of cells grows exponentially and their size decreases. From 1 you get 2, from 2 you get 4, etc. With an increase in cell mass, the gastrula turns into a morula. The morula looks like a spherical collection of cells. By day 7 after fertilization, the morula turns into a blastula. A fluid-filled cavity, or blastocoel, appears in the center of the embryo. The blastula enters the uterine cavity and is immersed in the mucous layer. This process is called implantation and involves the outer shell of the blastula, called the trophoblast. After implantation, trophoblast cells begin to produce human chorionic gonadotropin, an important hormone that supports pregnancy. Human chorionic gonadotropin can be detected in urine, where its presence is determined using a rapid pregnancy test. By the end of the first week, the size of the embryo is only 0.3 mm.

Embryo 2 weeks

On days 8-9 after fertilization, the blastula turns into a gastrula. In this case, the internal cells of the blastula are divided into 3 layers. The outer layer, or ectoderm, will develop into the nervous system and skin. The internal (endoderm) will turn into the cavity of the gastrointestinal tract. The mesoderm, the middle layer, will give rise to the musculoskeletal system (bones, ligaments and cartilage), muscles, kidneys, blood vessels and other internal organs. 10 days after fertilization it is already possible to get a positive pregnancy test result.

Embryo 3 weeks

At week 3, the embryo moves from the gastrula stage to the neurula stage. The ectoderm in the area of ​​the future spine forms a groove that gradually goes deep into the embryo. The edges of the groove are closed. A neural tube has formed that will become the brain and spinal cord. An embryo is formed that will become the baby’s heart.

At week 3, the placenta begins to form - the life support system of the embryo. The trophoblast and part of the ectoderm form the amnion and chorion. The amnion is popularly called the “shirt”. Amniotic fluid collects in the amniotic cavity. The chorion is a villous formation that also produces human chorionic gonadotropin. After some time, with the participation of the mesoderm, the placenta is formed from the chorion. By the end of 3 weeks, the embryo grows to a size of 4 mm.

Embryo 4 weeks

At week 4, the brain and spinal cord begin to form from the neural tube. At the same time, the heart makes its first contraction. Now it will not stop until the very end of life.

The rudiments of arms, legs, eyes, and internal organs are formed. Blood begins to flow in the blood vessels. Before this, the embryo received nutrients from the yolk sac, which, like in birds, contains reserves necessary for the initial stage of development. In addition, the yolk sac in mammals plays the role of the liver, bone marrow, and kidneys. It is the yolk sac that contains future germ cells, which migrate from it to the primordia of the gonads. After the appearance of the corresponding organs in the baby, it gradually disappears by the end of the first trimester.

Embryo 5 - 6 weeks

Embryo. 5 weeks from the moment of fertilization.

At 5 weeks, the umbilical cord is formed, which will connect the baby to the placenta. The umbilical cord contains arteries and veins. The length of the umbilical cord by the end of childbirth can reach 70 cm. At the 5th week, the arms and legs look like flippers, but individual details can already be distinguished. The first impulses begin to be generated in the nervous system - the basis of nervous activity. The head of the embryo is formed, and holes for the ears, eyes, mouth and nose appear in it. The length of the embryo reaches 1 cm.

Embryo. 6 weeks from the moment of fertilization.

At week 6, it is already possible to distinguish the features of the future face. Limbs and fingers are developing. The baby begins to make his first movements. The pigment that determines the color of the eyes is formed on the iris. At week 6, the embryo's heartbeat can be seen and heard using an ultrasound scanner or ultrasound. The placenta is fully formed. The rudiments of the lungs, kidneys, gonads, stomach and intestines are formed. Amniotic fluid already surrounds the embryo. The 6th week of pregnancy in Western countries is considered the optimal time for the first visit to a gynecologist. It is necessary to do an ultrasound, undergo a series of tests, and undergo an examination by specialized specialists.

Embryo 7 weeks

At week 7, the embryo's tail disappears. The gill slits close and become overgrown. Lungs begin to form. Limbs lengthen. The external genitalia and lymphatic vessels develop. The brain is enlarged. The heart is almost completely formed. The tip of the nose and eyelids are already visible. The size of the embryo reaches 1.5 cm.

Embryo 8 weeks

The kidneys begin to produce urine. Hair follicles form in the skin. Almost all vital organs have already been formed. Reflexes and feelings are triggered. Ears form, the face no longer looks like an alien from a science fiction movie. It is clearly visible that a person is growing. The bones are still made of cartilage, but later they will be saturated with calcium and turn into real bone tissue. This process will be completely completed only by the age of 25, long after birth. The size of the embryo is almost 2 cm.

Embryo 9 weeks

Now the baby can shake his fist if something worries him - his fingers can clench into a fist. The process of blood cell formation is transferred to the liver. The intestines unfold and fit into the abdomen. You can clearly see the ears, eyelids, nose, mouth and eyes. The face is fully formed. The rudiments of teeth are formed. The baby is already 3 cm tall and growing quickly.

Embryo 10 weeks

The baby's eyelids close. He will open them himself at 28 weeks. The respiratory system is almost completely formed. The skeleton and its structure fully correspond to a person. The arms and legs are lengthened to normal proportions. But the head occupies almost half the length of the body. This is due to the active development of the cerebral hemispheres, the cerebellum is growing. The external genitalia develop according to gender. You will soon find out if he or she is growing in your belly. The baby's blood acquires its own group and Rh factor. Height can reach 7-8 cm.

Embryo 11 weeks

The baby has a hairstyle. The fine hair on the head and body is called lanugo. They usually fall out by the time of birth. The skin is almost transparent, blood vessels are visible. The first foci of ossification form in the bones. White blood cells - leukocytes - appear in the blood. The arms are pulled up to the face, the baby can put a finger in the mouth. We begin to do exercises - the baby can actively move in the womb, but its size (10-15 cm) and low weight (30 g) do not yet allow the mother to properly feel these movements.

Embryo 12 weeks - 13 weeks

Embryo 12 weeks. Photo

During this period, you can visit a doctor and have an ultrasound examination done in 3D reconstruction mode. Here is your baby's first portrait. Ultrasound can determine the sex of the child with almost 100% accuracy. During an ultrasound, screening for developmental pathologies is carried out. The finger can now be sucked - the sucking reflex has appeared. The liver and pancreas produce secretions. Meconium is formed in the intestines - original feces. The formation of the genital organs is completed. The baby's height is about 15 cm, weight 40-50 g. Despite the fact that the child is so small, he is already a person. All organs are in their places, now his body will be more resistant to negative influences. All that remains is to grow. The first trimester is over.

Embryo 14 weeks -15 weeks

Eyebrows and eyelashes grow on the face. Now the baby’s face can express emotions - developed facial muscles allow him to make faces, cry, and grimace. Sweat and salivary glands appear. The heartbeat can be heard using an obstetric stethoscope.

Embryo 16 weeks -19 weeks

Marigolds appeared on my fingers. Taste buds on the tongue can sense taste, and receptors in the nose can sense smell. Mom may or may not like the foods she eats. Fully formed ears make it possible to hear sounds. Including mom's heartbeat. Recent research has led to an original practical application - soft toys are made for newborn children that reproduce the mother's heartbeat. It is believed that a calm, measured heartbeat calms the baby. Try not to be nervous. The eyes begin to discern light.

And of course, during this period, mothers begin to feel the baby’s movements inside them. There is feedback from the mother. The baby can sleep and be awake, this is noticeable by periods when no movements are felt. Baby's height is 20 cm and weight is up to 250 g.

Embryo 20 weeks -30 weeks

Did you feel the kick? Now the baby communicates with his mother this way. If mom is sad, upset about something, or there is loud music around, it’s smoky, stuffy, the baby violently expresses his opinion. At first it’s timid, but by the end of pregnancy this method of communication will no longer cause tenderness. Constantly getting kicked from the inside can be quite painful. A sudden noise or fright of the mother leads to a similar response from the child. Protective reflexes arise.

In the lungs, the formation of respiratory alveoli is completed. Fingerprints form on hands. Brain development occurs at the fastest rate. Neural connections are formed. The baby can blink. The immune system is formed. The respiratory organs are developed enough to provide breathing in the event of premature birth, but sometimes only with medical assistance and special equipment. Adipose tissue appears. By 30 weeks, growth reaches 40-43 cm, weight up to 1.5 kg.

30 weeks - 38 weeks

Childbirth is approaching. The baby turns head down in preparation for birth. Vellus hair disappears, with the exception of the shoulders. The lungs actively produce a substance called surfactant. It is necessary for breathing atmospheric air, protects the respiratory sacs and prevents them from sticking together. Without surfactant, the lungs may not expand fully. In premature babies, this is the main cause of oxygen deficiency and death. By the time of birth, the baby will be 52 cm tall and weigh about 3 kg.

Childbirth occurs on average at 38 weeks from conception, but doctors usually measure gestational age in obstetric weeks, from the date of the last menstrual period. In this case, 38 weeks of intrauterine development is equal to 40 obstetric weeks. Embryology, the science that studies the development of the embryo, considers a child to be an embryo from conception to birth. At 38 weeks, the embryo develops in the uterus. But, from 13 weeks, the embryo, for the convenience of doctors, is already considered a fetus. From the 13th week of development, the embryonic period passes into the fetal period. This is also related to legal aspects.

Bearing and giving birth to a child is a difficult ordeal for any woman. But the delight and joy of motherhood are many times greater than any other feelings. There will be sleepless nights, and great anxiety at moments when the baby is sick, and worries. Kindergarten, school, adult life and the child’s problems will always come first for you. After all, you are now connected forever.

Pregnancy is a physiological process in which a fertilized egg, first called an embryo and later called a fetus, develops in the uterus. The duration of pregnancy is about 9 astronomical or 10 obstetric months. Traditionally, the development of pregnancy is considered by trimesters. However, knowing how the embryo develops week by week is also of interest.

Embryo or fetus?

In medical science, you can often find two concepts related to the period of gestation - “embryo” and “fetus”. What's the difference between them?

Intrauterine development of the fetus is conventionally divided into two stages:

1. Embryonic – lasts the first eight weeks. At this time, the embryo that develops in the uterus is called an embryo.
2. Fetal (from 9 weeks until the moment of birth). At this stage, the fetus resides in the mother's womb.

How the child, his internal organs, systems, will develop during various periods of intrauterine development of the fetus is determined by the genetic code that was transmitted by the germ cells of the mother and father.

1-10 weeks

1 Week

Speaking about the first week of pregnancy, you should clearly understand what exactly is taken as the starting point. If we talk about obstetric weeks (regardless of whether there is a multiple pregnancy or not), then we take into account the first day of the last menstruation of the cycle when the woman had unprotected intercourse and, accordingly, conception occurred.

Sometimes the moment when contact occurred without the use of contraceptives is taken into account. By counting by days, you get the third obstetric week. If we take into account the date of the start of the delay in menstruation, we get the fifth. In gynecology, when analyzing the intrauterine development of the fetus by week, they often focus on obstetric timing.

The first few days, even if it is a multiple pregnancy, are not characterized by any clear signs. This time is the beginning of the menstrual cycle. The level of hCG (human chorionic gonadotropin) is within normal limits (5 IU/ml for non-pregnant women).

HCG fluctuations at the first stage are evidence of:

• previous abortion or miscarriage;
• taking hormonal drugs.

2 week

This time is marked by the fact that the zygote continues to mature in the uterus or fallopian tube, which, under favorable circumstances, will become a developing pregnancy.

Towards the end of this period, there comes a time when, after conception, the egg attaches to the wall of the uterus.

This can be indicated by discharge that is similar in consistency to egg white and even bloody. Small discharges of blood are relative evidence of the attachment of an egg to the wall of the uterus and the appearance of an embryo. Heavy discharge during this period of pregnancy is not the norm.

3 week

It was at this time that it can be argued that conception occurred. The fruit is extremely small, its size is 0.15-0.2 mm in length, and its weight is only 2-3 mcg. If fertilization does not occur, the woman may begin her period several days earlier. When maintaining a special calendar, it is easy to notice a slight shift.

If the pregnancy was planned, significant bleeding may indicate a threat of miscarriage.

4 week

The embryo develops so actively that a woman may begin to feel the first signs of her changed status, especially if the pregnancy is multiple. There is swelling of the mammary glands, the nipples become sensitive. Menstruation is delayed, and scanty bleeding is sometimes observed.

At this time, there is an increased risk of fetal developmental abnormalities due to excessive physical activity, an infectious disease accompanied by high fever, and abuse of alcoholic beverages.

HCG levels only increase in the blood. On an ultrasound, you can see the corpus luteum, which provides nutrition to the embryo before the placenta begins to fully function, and is also involved in the production of progesterone, the so-called pregnancy hormone.

The size of the embryo increases. It is already 5 mm in length.

The fruit weighs 3.5 g and length is from 4 to 7 mm. The rudiments of limbs, fingers, eyes, ears, slits for the nose and mouth, and some glands and systems begin to form. The size of the uterus changes.

An ultrasound specialist at this time can tell whether a woman is developing a multiple pregnancy or whether she will have one child. During the examination, the diameter of the amniotic sac is determined, as well as the coccygeal-parietal size and the “growth” of the fetus. The last digit will appear in the results throughout the first trimester.

Changes in the body become more noticeable. Some women note a slight increase in body temperature to subfebrile levels. However, if the condition begins to fit the description of a cold, you should immediately consult a doctor.

week 6

The woman begins to show signs of future motherhood. The uterus reaches the size of a plum - an experienced gynecologist is able to feel it during the examination. If there is a multiple pregnancy, an ultrasound will show two fetal and yolk sacs. The examination will also allow you to see small tubercles - here, over time, the upper and lower limbs will appear, and you can also hear the heartbeat using a special device. Facial features gradually emerge. The embryo reaches a length of 4-9 mm, its weight is no more than 4.5 g.

week 7

The fetal heart becomes four-chambered and large blood vessels are formed. The first trimester is marked by the continued development of all internal organs and systems. Weight – 1 g, coccygeal-parietal size is 13 mm. The unborn child gradually begins to straighten up. The brain is developing rapidly.

The face and upper limbs are improved. The umbilical cord completes its formation and a mucous plug forms.

The size of the fruit increases significantly - 14-20 mm in length, it begins to move. By the middle of the first trimester, the face acquires more and more human features. The formation of organs and systems has been completed, some of them are actively functioning. The optic nerve is born, the rudiments of the genital organs appear.

Week 9

The coccyx-parietal size of the unborn child reaches 22-30 mm, weight - 2 g. The cerebellum, pituitary gland, middle layer of the adrenal glands, lymph nodes, and genitals are actively formed. The functioning of the cardiac and nervous systems is improved. The upper and lower limbs begin to move, bend, and muscles appear. The fetus gains the ability to urinate.

The critical first stage of development ends for the fetus. Weight reaches 5 g, and height – 30-40 mm. The heart rate reaches 150 beats per minute. The limbs are fully formed, you can see the joints and fingers. The foundation of baby teeth is laid, which obliges the mother to keep a food calendar and mark the consumption of dairy products in it. Most of the gastrointestinal tract organs have already completed their formation.

11-20 weeks

11 week

The critical stage of development is virtually over. The weight of the fetus reaches 8 g, the “height” is 5 cm. From this moment, the embryo enters the fetal stage. The heart is working fully, the formation of blood vessels is completed. The placenta becomes dense. The liver occupies 10% of the body. The intestines make the first movements similar to peristalsis.

The genital organs are increasingly formed. Eye color is determined and the sense of smell appears. Palms and fingers become sensitive.

12 week

Critical moments for fetal development depend more on the health and lifestyle of the mother. The body length ranges from 6-9 cm. The unborn child already has fingers and nails are forming. The gastrointestinal tract organs are completing their formation. The immune system is improved.

The first trimester ends, the critical cycle is completed. The baby teeth are fully formed, muscle and bone tissue continues to form, and the digestive system develops. The genital organs are differentiated. The child’s “height” reaches 8 cm, weight – 15-25 g.

Week 14

The baby is actively growing and developing. Its weight is 30-40 g, and its height is from 8 to 10 cm. The resemblance to a person is increasing. In case of multiple pregnancy, the expectant mother can feel the movements of the children, who are becoming more and more active. The bone skeleton grows, ribs are formed. The movements of the diaphragm resemble breathing. All organs and systems are fully formed. The child has an Rh factor and blood type.

Starting from the 15th week, the baby’s cerebral cortex begins to form. The process will take most of the second trimester. The endocrine system, sebaceous and sweat glands are activated.

Taste buds are fully formed, breathing movements are improved. The baby’s weight reaches 70 g, from the tailbone to the crown it is already as much as 10 cm. But even with multiple pregnancies, this does not interfere with free movements.

Week 16

By the first half of the second trimester, the baby is already 11 cm tall and weighs 120 g. The neck has taken an even position, the head rotates freely. The ears and eyes gradually rise upward. The liver takes over digestive functions. The development calendar is becoming busier. The composition of the blood is completely formed.

The immune system turns on, interferon and immunoglobulin are produced. The baby is able to protect itself from infections coming from the mother. But they all continue to be critical for the small organism. The fetus develops a layer of fat. If a girl grows, by the middle of the second trimester she will have a uterus. A person's height is 13 cm, weight is 140 g. He is able to hear sounds from the outside and feel emotions. From the point of view of emotional and mental development, week 17 is critical - establishing contact is extremely important.

The second trimester is approaching the middle. The upper and lower limbs of the fetus, phalanges of the fingers, and prints on them are fully formed. Fat tissue, the immune system and the brain continue to actively develop at week 18. The rudiments of molars are formed.

A reaction to light appears, and hearing increases. The calendar must include the date of the first movements and their frequency. Fetal height is 14 cm, weight – 200 g.

There is a big leap in development. Movements become more orderly. The respiratory system is improving. The body is covered with vernix. By week 19, the head rotates freely and is held in one position. Weight reaches 250 g, and height – 15 cm.

Week 20

The child is already fully formed, his organs are improving. By week 20, the heartbeat can be heard with a regular stethoscope. The limbs are fully formed. The sensations of sounds become more acute. The length is 25 cm, and the weight is about 340 g. The movements are more noticeable for the mother.

21-30 weeks

By 21 weeks, the baby gains height - 26.7 cm and weight - 360 g. But there is enough room for active movements. The digestive system works more actively, the fetus constantly swallows amniotic fluid. Muscle and bone tissue are strengthened. The spleen is involved in the work of the body.

Week 22

The period is marked by a significant increase in weight - up to 500 g. Height also changes - as much as 28 cm. The fetus at these times is viable even if it is first born. The brain and spine are fully formed. Reflexes are improved. The heart increases in size.

Week 23

By the 23rd week the fetus is sufficiently formed, the digestive system is fully functioning. Adipose tissue accumulates. The genital organs are clearly differentiated.

The baby's height reaches 29 cm, and his weight is 500 g. The spleen becomes more active.

Externally, the fetus already looks like a child. Due to the small amount of adipose tissue, the weight is only 600 g with a height of 30 cm. By week 24, independent production of growth hormone begins.

The respiratory system enters the final stage of development. Reflexes and sensory organs are improved. A sleep and wakefulness pattern is developed. The baby begins to listen to the mother’s emotions. The movements become sensitive.

The fetus gained weight to 700 g and grew to 34.5 cm. The resemblance to a newborn increases.

The lungs are preparing for the first independent breath. The hematopoietic function is completely carried out by the bone marrow.

The sense of smell is highly developed, the child senses the mother’s mood swings. The bone skeleton is actively overgrown with muscles. Testicles and vagina appear.

The fruit acquires individuality. The eyes begin to open. The child is able to recognize the voice of his mother and father. Bone tissue is strengthened. The lungs are finally taking shape. The brain produces various hormones. The baby weighs 750 g, he is as much as 36.5 cm long. He sleeps 16-20 hours. Movements can be noticed by others.

Week 27

The fetus weighs 900 g by 27 weeks. Growth becomes more active. The endocrine system also enters a new phase of activity. The stability of a child’s pancreas determines the development of metabolic processes and mental abilities. The production of surfactant, a substance that allows the lungs to open after birth, stabilizes.

The amount of subcutaneous fat increases. The mother feels the baby’s training even more strongly.

Bone tissue continues to strengthen. Alveoli appear. The future little man can weigh 1 kg or more. Having reached 38.5 cm in height, the baby begins to feel a lack of free space in the uterine cavity, although this does not in any way affect his activity.

Week 29

The baby's body is gradually preparing for the upcoming birth. Thermal regulation and the functioning of the immune system are improved. The blood composition has been stabilized. The digestive system is completely ready to digest food. The gaze begins to focus. The skin gradually brightens and loses wrinkles. Subcutaneous fat increases, muscle tissue strengthens.

Week 30

The child’s weight reaches 1500 g. Gradually the nervous system “turns on.” The liver accumulates iron. The work of the heart acquires sexual differentiation - in boys it beats more calmly than in girls. Typically, by this time the fetus is in the position from which it will be born. Movements become calmer. Eyes open.

31-40 weeks

The child may already weigh more than 1.5 kg. The liver acquires the ability to cleanse the blood.

Surfactant production continues. The connection between peripheral nerve cells and the brain is established. Having touched the cornea, the baby will definitely close his eyes. The calendar of intrauterine development is gradually ending.

Week 32

The active growth phase continues. Organs and systems are fully functioning. The skin and appearance take on a familiar appearance. Lanugo, the original down, gradually disappears.

The baby is finally in position for birth. The skull remains soft.

At this time, the weight reaches 2000 g. Muscles and subcutaneous fat continue to build. Body parts become more proportional, many body systems work fully. The child is able to express emotions. The kidneys are prepared for their main function - filtration.

34 week

Fetal development is coming to an end. Individual traits become more and more obvious. Gastrointestinal tract training is more active.

By these days, organs practically do not develop. Activity is observed in terms of building muscle and fat tissue. Every week the baby gains up to 220 g. The skin is deprived of lanugo and completely smoothed out. Shoulders are rounded.

The body continues to improve. Iron continues to accumulate in the liver, and vital systems are being adjusted. The baby actively sucks his thumb in preparation for the upcoming breastfeeding. Most children occupy, that is, head down.

Week 37

The fruit is fully formed. The gastrointestinal tract is ready to receive and digest food, peristalsis is activated. Heat exchange processes have been established. The lungs are ripe. Iron accumulates in the liver. Height and weight increase weekly.

The baby is ready to be born. In male children, the testicles descend into the scrotum. The skin takes on a pink tint.

The fetus is fully formed, its organs and systems are ready for independent functioning. Reaction to sounds and light is developed. There is no original lubricant on the surface of the skin.

week 40

The baby's height is approximately 54 cm, weight - from 3 to 3.5 kg. The formation is completely completed.

The appearance of a child in the family- a desired and very exciting moment for which young parents begin to prepare as soon as they learn about pregnancy. Therefore, information regarding fetal development by month of pregnancy is always very important and informative. In addition, the birth of a new life and the development of a little person will also be interesting to people who are not yet thinking about procreation, since nature provides for a simply unique process. It consists of three stages: first, second and third trimesters, during which the formation of the child occurs.

First months of pregnancy- the most important for the further development of the fetus, since right now the fertilized egg attaches to the wall of the uterus and slowly begins to turn into a child.

Whether it will take hold or not, and how correctly the further formation of all the little person’s systems will proceed, depends on a number of factors. Let's try to understand the features of this process week by week.

First week (days 1-7)

We can talk about the beginning of pregnancy when fertilization of a female egg by a male cell (sperm) occurs; they talk about this in biology lessons at school, but what happens next is not studied in detail.

Most often, this process occurs in the fallopian tube (in its ampullary section), but within a couple of hours after the “meeting,” the fertilized egg quickly begins to divide, and then descends through the fallopian tube into the uterine cavity. This entire process takes approximately five days.
As a result, a multicellular organism appears in the uterus, somewhat reminiscent of a blackberry (in Latin “morus”), from which the embryo at this stage received the name “morula”.

On seventh day it penetrates the uterine wall, and the villi of its cells (external) connect with the blood vessels of the female organ, which later form the placenta.

The remaining outer cells become the basis for the development of the membranes of the embryo and its umbilical cord. As for the internal cells, they become the beginning of the internal organs of a small person.

Important! When the egg attaches to the wall of the uterus (implantation), a woman may experience bleeding from the vagina, but this is a completely normal phenomenon and there is no need to worry.

Second week (8-14 days)

The cells of the embryo continue to grow into the mucous membrane of the uterus, after which not only the placenta, but also the umbilical cord and the neural tube begin to form - very important component, from which the nervous system of a new person is subsequently formed.

During this period there should be a complete absence any heavy bleeding, because their presence indicates the possible presence of a disease, for example, endometrial hyperplasia or impaired ovarian function, but a woman may also begin menstruation, which indicates an unsuccessful attempt to become pregnant.

True, it is too early to talk about a full-fledged miscarriage, since the fetus has not yet become one, but for now is only an egg.

Third week (15-21 days)

One of the most difficult and important periods, since right now all the important systems and organs of the unborn child begin to form, the respiratory, circulatory, nervous, digestive and excretory systems are formed, and in the place where the fetal head will soon form, a wide plate appears - the basis for further formation and development of the brain.
Important Feature this week is the beginning of the embryo's heartbeat. Now we can say with confidence that conception has occurred, although the possibility of miscarriage cannot be ruled out.

Did you know? In the third week of pregnancy, the body weight of the unborn baby is only 2-3 mcg, and the length of the “little body” is from 0.15 to 0.2 mm.

Fourth week (22-28 days)

The laying and formation of fetal organs continues, from which the intestines, liver and lungs can be distinguished. The performance of the still tiny heart is increasing more and more.

At the end of the first month During pregnancy, folds of the body are formed in the embryo, and a spine (notochord) is formed, dividing the embryo into two halves with a clear separation of the limbs. On the head of the unborn baby, pits begin to form, which will later become eyes.

Fifth week (29-35 days)

According to the pregnancy calendar, it means the beginning of embryo development in the second month (obstetric).

At that time in a little man (his height from the crown to the coccyx varies between 1.5-2.5 mm), all organs of the digestive (pancreas and liver), respiratory (lungs, larynx, trachea), genital (formation of the precursors of the reproductive organs) begin to take shape cells), nervous (formation of parts of the brain) systems, and also the further development of sensory organs - the eyes and inner ear.

Besides, in the fifth week The umbilical cord is already noticeable and the baby’s limbs continue to form, and the rudiments of marigolds are formed on them. On the front part the nasal cavity and upper lip are already visible.

Many women at this stage clearly feel pregnancy, because the uterus sharply enlarges (outwardly this is not noticeable at all) and puts pressure on the bladder. appear first signs of toxicosis and increased sensitivity to various odors.

Sixth week (36-42 days)

By the sixth week, the unborn baby reaches a length of 4-9 mm. His heart beats very quickly, although it is still far from a full-fledged organ - no atrium. The placenta is being formed, which is just beginning to perform its direct functions, and blood circulation with the embryo has not yet been established.

Continue actively form all parts of the brain, and if you make an encephalogram, you can record the signals sent by the tiny brain. The formation of facial muscles also begins, the eyes of the embryo become more pronounced and are not covered by eyelids.

Upper limbs lengthen slightly, while the lower ones are still in their infancy. In the digestive system, sections of the gastrointestinal tract (small and large intestines, as well as the stomach) begin to form.

The pancreas and liver almost completely complete their formation.

Seventh week (43-49 days)

The length of the embryo body is approximately 10-13 mm. The placenta becomes much thicker, and the baby and mother are already firmly connected by the umbilical cord, through which the uteroplacental circulation is finally formed.

It is noteworthy that the little man still there is a tail, which will soon disappear, and the baby’s legs remain like small fins, while the upper limbs can already bend at the elbows, the rudiments of the fingers begin to be visible. The shoulders and forearms are clearly visible.

Fetal eyes covered with eyelids that protect them from drying out, and the child sometimes opens his mouth slightly. The nose and nasal fold are formed, two paired elevations appear on the sides of the head: from them the auricles then develop.

It was at this time a mucus plug forms, which will close the cervix and protect the baby from harmful environmental factors.

Eighth week (50-56 days)

The baby's body gradually straightens and its length (measured from the tailbone to the crown) corresponds to 20-21 mm (by the end of the week). Continue their formation basic body systems: digestive, cardiovascular, respiratory (especially lungs), urinary and reproductive (in boys, testicles begin to develop).

The sweat and salivary glands are still at the stage of formation. The baby’s face also becomes more familiar to an adult: the eyes are well defined, the nasal cavity and ears are formed, and the process of lip formation is completed.

And the head and all the limbs begin grow rapidly, ossification of the long bones of the legs and arms also occurs. On an ultrasound, you can notice small fingers with no membranes between them. The eighth week is the period of formation of the optic nerve.

The embryo begins to move, but due to its small size, the woman does not feel these movements in any way.

Important! It is in the eighth week that the embryonic stage comes to an end and the embryo is already called a fetus.

Ninth week (57-63 days)

The length of the fruit is in the range of 22-31 mm. The blood vessels of the placenta continue to improve, the system of bones and muscles intensively develops, in particular, the joints of the legs and arms are formed.

Peculiar changes are also noted in the functioning of the cardiovascular system: the heart is already capable of making 150 beats (in 1 minute) and pumping blood through the blood vessels. The brain is still actively growing and developing, the structure of the cerebellum is emerging, and the pituitary gland is being formed.

Also The adrenal glands begin to actively develop, while producing hormones important for the body, lymph nodes develop. At the same time, cranial, spinal and intervertebral nerves appear.

In the unborn child The cartilage tissue also improves, which at this stage is expressed in the design of the auricles, the cartilage of the larynx and the formation of the vocal cords.

At nine weeks the fetus looks like a small pea pod, which through the umbilical cord removes its waste products into the mother’s body.

Tenth week (64-70 days)

The fruit (from crown to tailbone) has already reached a length of 35-40 mm. The most interesting change is the disappearance of the ponytail and the formation of the buttocks, but this, of course, is not the only important change.

Further, the nervous system (already divided into central and peripheral) of the fetus is improved, which can now perform not only chaotic movements, but also shudder in response to a stimulus (the first reflexes are formed).

Eg If the baby accidentally touches the wall of the uterus, he may turn his head, bend or straighten his arms and legs, or even be pushed to the side. At the same time, the development of the diaphragm is coming to an end, which as a result will be directly involved in the breathing process.

With high speed the brain is formed and in one minute up to 250 thousand neurons can be created in it.

Eleventh week (71-77 days)

The body of the unborn child at this time still remains disproportionate: the large head stands out strongly against the background of the small body, and the arms are longer than the legs, bent at all joints and located in a tucked state. By the end of the eleventh week, a fetus measuring 4-5 cm is in the woman’s womb.

At this time, the placenta already fully performs all the functions assigned to it and provides the little person with a sufficient amount of oxygen and micronutrients. In addition, it is she who pushes metabolic products and carbon dioxide out.
The further formation of the baby’s eyes is also noticeable, because the iris appears, which will ultimately determine his eye color.

Appear in the fetal blood first lymphocytes, directly involved in the formation of immunity.

Did you know? At this stage of intrauterine development, the unborn child's liver makes up 10% of his entire body. The intestines also make their first movements (something like peristalsis).

According to experts, at the 11th week the formation of the little person’s sense of smell also occurs.

Twelfth week (78-84 days)

Fruit size(from the crown to the coccyx) approximately within 50-60 mm, its genital organs (male or female) are actively developing and the digestive system is improving. As for the latter, the most noticeable is the lengthening of the intestine and its loop arrangement (exactly like in an adult).

The child is already can swallow amniotic fluid, clench and unclench your fingers, as well as grab your thumb with your mouth and actively suck it. In addition to red blood cells, leukocytes (white blood cells) also appear in the baby’s blood, and single respiratory movements can also be recorded.

Of course, before the moment of birth, the fetus is not yet able to breathe on its own and its lungs do not function properly, but it is quite capable of performing rhythmic movements chest.

Did you know? Starting from the 12th week, unique patterns - fingerprints - are formed on the pads of the tiny person's fingers.

Thirteenth week (85-91 days)

Future baby size reaches approximately 70-75 mm, and the proportions of his body begin to actively change: the lower, upper limbs and torso become longer, and the size of the head does not seem so large.

All these changes the expectant mother can see on the monitor when undergoing an ultrasound scan, especially knowing in advance about the stages of pregnancy and the developmental features of her child week by week.
In addition, week 13 is also significant as the beginning formation of baby teeth, which are located under the lower and upper jaws.

By the way, there are crumbs in the intestines the first villi appear, which after birth will begin to take a direct part in the process of digestion and promotion of food. The pancreas produces the first insulin, and the vocal apparatus is also actively forming.

The baby’s emotional sphere also develops, which learns to respond to sounds, silence, light and shadow, heat and cold, becoming more and more awake.

Fourteenth week (92-98 days)

By the end of the 14th week, the fetal body becomes longer and is already 8-9 cm, and its proportions take on an increasingly familiar appearance. The first hairs are already visible on the head, although they are still quite thin and do not have a specific color.

The surface of the body is covered with sparse vellus hairs.

The bones and muscles of the fetus develop and improve, the first ribs appear, and the development of the bladder, ureters and kidneys, which actively secrete urine that mixes with the amniotic fluid, is completed.
Swallowing amniotic fluid, a child can determine its taste by reacting to sweets with rapid swallowing reflexes or weak sips to bitter ones.

My work begins cells of the pancreas and pituitary gland. In boys, the prostate gland actively develops, and the ovaries of girls are located in the pelvic region.

If you do an ultrasound on quality equipment, then with a high degree of probability it will be possible to find out the gender of your baby.

If we look at the stages of pregnancy in detail by week, then starting from the fifteenth we can talk about the second trimester of pregnancy. Before this time, the fetus has already strengthened in the uterus, all its main systems and organs are almost formed, which reduces the risk of unforeseen situations.
However, quite Expectant mothers should not relax, since there are still many important stages of the baby’s development ahead.

Fifteenth week (99-105 days)

With the beginning second trimester, the fetus weighs approximately 70-75 g, and its length (still measured from the crown to the tailbone) is 10 cm. Despite the fact that the child’s head is large, the growth of his limbs and torso begins to outstrip it.

At the same time, if desired, you can find out the blood type of the little man, and he also begins to excrete original feces (meconium).

However, the most important process in week 15 is the beginning of the formation of the cerebral cortex, which will take place throughout the fourth month.

It is also impossible not to remember activation sweat and sebaceous glands.

Sixteenth week (106-112 days)

At this time, the baby’s body length is about 12 cm, and the weight increases to 100 g. At 112 days after conception, the fetus is considered fully formed, since it already has all the systems and organs.

However, the fetal skin is still quite thin, and subcutaneous fat is almost completely absent, which is why blood vessels are clearly visible. Eyebrows and eyelashes are clearly visible on the face, and nails are partially formed, covering only part of the nail plate.
If we consider the baby With the help of modern ultrasound technologies, you can see how he frowns, breaks into a fleeting smile and makes grimaces. The child is already holding his neck and is able to turn his head, and his ears and eyes are getting closer and closer to their proper place.

Seventeenth week (days 113-119)

Seventeenth week of pregnancy begins with a fetal weight of 120-150 g and a body length of 14-15 cm. The baby’s skin is still as thin, but fatty tissue is intensively formed under it. Baby teeth continue to develop and begin to become covered with dentin.

The reaction to sound stimuli becomes more pronounced and many experts claim that from the beginning of the 17th week the fetus begins to hear (sharp sounds force it to increase activity).
Also the location of the fetus changes: the head rises and takes an almost vertical position, the arms are bent at the elbow, and the fingers are clenched into a fist. The child’s immune system is activated, as a result of which interferon and immunoglobulin are produced in the body. This allows the little man to protect himself from the mother's infections.

At the same time The small heart, vigorously pumping blood, also completes its development. There is also an opinion that the 17th week is critical for the mental development of the baby, therefore both mother and father need to contact him more often, talking affectionately.

Eighteenth week (120-126 days)

At this stage, we can say that the second trimester is approaching the middle. The fruit reached 20 cm in length (from the coccyx to the crown) and gained up to 200 g of weight. His limbs (both upper and lower) are already fully formed, they have phalanges of fingers and even prints.

Continue their development brain and immune system, hearing improves, and a pronounced reaction to light appears. The fat layer is actively formed and even the rudiments of molars are laid.

If this is not the first pregnancy for a woman, then with a high degree of probability she will feel the first movements of his baby. The norm is approximately 10 light tremors per day.

Nineteenth week (127-133 days)

At that time we can talk about a significant leap in fetal development. Movements are more orderly, the respiratory system is improved, and the body is covered with vernix lubrication. The baby's weight reaches 250-300 g, and the length of the fetus varies around 22-23 cm.

At the same time, the size of the head for the first time begins to lag behind the indicators of the torso and limbs, which are actively lengthening.

The pituitary gland, gonads, adrenal glands, pancreas, thyroid and parathyroid glands work intensively. The composition of the blood also changes greatly; in addition to leukocytes and erythrocytes, lymphocytes and monocytes also appear in it.

On this term The baby's kicks are felt not only by the expectant mother, but also by the father if he places his hand on his stomach.

Twentieth week (134-140 days)

The length of the baby's body increases to 25 cm, and the weight is already about 340 g. The skin remains the same thin and covered with vellus hairs, often remaining until birth.

However, subcutaneous fat begins to develop more intensively.
Also at 20 weeks During intrauterine development, the baby develops a blinking reflex, coordination of movements improves and facial expressions become more pronounced.

Having a regular stethoscope, you can calmly listen to the rhythm of his heart, which becomes more stable.

Twenty-first week (days 141-147)

When the fetus reaches 21 weeks of intrauterine development, its growth is measured from the heels, and not from the tailbone, as was previously the case. Now it is approximately 26.7 cm, with the baby weighing about 360-380 g.

Every day subcutaneous adipose tissue is getting bigger, the fetus even develops folds on its body. The digestive system begins to work more actively and the fetus constantly swallows amniotic fluid.

Bone and muscle tissue continue to strengthen, and the spleen also joins the actively working endocrine glands.

Despite his considerable growth, the baby still feels free in the womb of his mother and can occupy almost any position.

Twenty-second week (148-154 days)

Little man size at this stage it increases to 28 cm, and the weight will be in the range of 450-500 g. The head becomes proportional to the body and limbs, and the legs are almost constantly in a bent position.

The child’s spine is characterized by the presence of all ligaments and joints, but the bones continue to strengthen.
The active development of the nervous system is observed: the baby begins to be interested in his face, legs and arms, he brings his fingers to his mouth with interest and tilts his head.

The heart is significant increases in size, since the cardiovascular system is still being improved.

Important! If for some reason the pregnancy is terminated at 22 weeks, modern medical technologies allow such a child to be born, since it is considered fully viable.

Twenty-third week (148-154 days)

In addition to further development of all main systems and organs a small person, who, by the way, at 23 weeks weighs 500 g and has a height of 28 to 30 cm, pigment begins to be synthesized in the skin, giving the skin a bright red color.

Due to the thin subcutaneous fat layer, the fetus appears very thin and strongly wrinkled, and lubricant is mainly concentrated in the folds of the body.
The frequency of respiratory movements increases and is now equal to 50-60 times per 1 minute and the swallowing reflex is still well developed, as a result of which the child swallows part of the amniotic fluid.

Interesting that even such a baby can have hiccups, which a woman feels as rhythmic movements for a couple of minutes.

Moreover, some scientists believe that from this time on, baby can dream, since it was possible to record REM sleep phases in the fetus.

Twenty-fourth week (162-168 days)

The fruit, which was asymmetrical until recently, is increasingly becomes like a child. There is still a little adipose tissue, so the weight gain is not too noticeable and the baby weighs 600 g (height is approximately 32 cm).

It should also be noted that it is at week 24 that the small body begins to independently produce growth hormone, allowing it to grow faster in the future.

The fetus has already taken up almost all the space in the uterine cavity, but can still turn over.
By the end of the sixth month The sense organs have developed well and vision begins to develop (when the abdomen is illuminated with bright light, the baby immediately squints his eyes tightly and turns away).

Completes its development and respiratory system, the bronchial tree and lungs are already fully formed, coated with a special substance - suffracant (prevents the capillary sacs from drying out and closing when inhaling air after birth).

Sweaty and greasy glands are also distinguished by more streamlined work than at previous stages of development, but the main thing for the mother is that it is at this time between her and the future baby an emotional connection is formed: fear, anxiety, melancholy and other negative emotions cause similar feelings in a child.

Twenty-fifth week (169-175 days)

The child grows to 30-34 cm and already weighs 650-700 g. The skin becomes more elastic, there are fewer folds, but it still remains thin and has a large number of capillaries, coloring it reddish.

The front part is even more shaped and the eyes, eyelids, eyelashes, eyebrows, lips, cheeks and ears are already clearly visible.

There is a rapid development of bone marrow - now the main component in hematopoiesis.

Also observed important processes during lung formation: alveoli appear, which before birth are in a “deflated” state (without air), and from the side of the reproductive system, the appearance of the testicles (in boys) or vagina (in girls) is noticeable.

Twenty-sixth week (176-182 days)

The height of the little man at this stage of his development is approximately 36 cm, with a weight of about 750-760 g. Continues to increase muscle mass and fat layer, bones are strengthened and permanent teeth develop further.
In general, the child has already acquired all his personality traits: eyelashes and eyebrows have taken their places, ears have taken shape and now they protrude slightly from the head.

The lungs take their final shape and take their proper place, that is, the child is now completely ready breathe on your own after its birth. The eyes also begin to open, the fetus already recognizes the voices of its parents.

The last stage of pregnancy, which means that you will soon meet your baby and hold him in your arms.

You have already learned how a child grows in the previous 26 weeks, that by this time all the main systems and organs are formed, but the process of its full development during pregnancy is not yet completed, a lot of interesting things await you.

Twenty-seventh week (183-189 days)

At this time The next phase of active growth of a small life begins. The baby's weight is already 850 g with a body length of 37 cm.

All organs of the endocrine and other systems (including the pancreas and thyroid glands, as well as the pituitary gland) are functioning well, and the fetus itself is very active (but can still move freely into the uterine cavity).

At the same time its own metabolism begins to develop. The skin becomes lighter, and underneath it the muscle tissue increases more and more.

Twenty-eighth week (190-196 days)

The baby's weight has reached 950 g, and his length is 38 cm. Fatty tissue continues to accumulate, vellus hair begins to fall out (only on the back and shoulders). Eyebrows, hair on the head and eyelashes acquire a darker color.
The baby opens his eyes much more often, but the cartilages of the ears and nose remain just as soft, and the nails do not reach the edge of the phalanx of the fingers.

Remarkable that it is at this time that one hemisphere of the brain begins to work more actively: if the right hemisphere, the child will be left-handed, and if the left hemisphere will be right-handed.

Twenty-ninth week (197-203 days)

The child is increasingly preparing to enter the big world: The immune system copes with its functions quite well, and the body’s heat regulation also improves its functioning. The baby's weight is now about 1200 g, and his height reaches 39 cm.

Such dimensions significantly reduce the free space in the uterus and all movements of the fetus are expressed in infrequent pushes with arms and legs.
The organs and systems of the small organism continue to improve; for example, up to 500 g of urine is excreted by the kidneys every day.

falls on the cardiovascular system, although the blood circulation of a little person is not yet the same as the blood circulation of a newborn.

With the beginning of the 29th week, the amount of vernix lubrication begins to decrease, and the skin becomes increasingly lighter and smoother.

Thirtieth week (204-210 days)

The child’s weight continues to grow and reaches 1300-1350 g, although the length of the body remains approximately the same - 38-39 cm. Fatty tissue continues its increased accumulation, which increasingly straightens the folds in the skin.

Lack of space in the womb forces the baby to take a certain position: curl up and cross his legs and arms.
Also continue alveoli develop, surfactant is actively produced, that is, the child is preparing to start breathing independently.

Brain development is characterized by the appearance of a large number of convolutions and an increase in the area of ​​the cortex.

Nerve cells function, fibers are formed, around which a protective myelin sheath appears.

The child's liver accumulates iron, thanks to which the baby will be supplied with blood cells throughout the first year of his life.

Thirty-first week (211-217 days)

The baby, who by this time already weighs 1500-1700 g and has a height of 40 cm, has significantly changes in wakefulness and sleep patterns.

Motor activity decreases, although the child kicks well while awake. In addition, these processes are accompanied by the closing or opening of fully formed eyes.

Did you know? At birth, the iris of all children has the same blue color and only after some time begins to change.

The volume of the brain during this period is 25% of the volume of this organ in an adult.

A connection is established between nerve cells, and the nerve fibers continue to be “overgrown” with protective sheaths. Further formation of all organs and systems continues.

Thirty-second week (218-224 days)

If at the previous stages the child has not yet turned upside down, then this usually happens at this stage.

Now the baby weighs approximately 1800 g with a height of 42 cm, and therefore there is less and less space for him. Active accumulation of fatty tissue smoothing the skin.

The internal organs are still improving: the endocrine system secretes hormones, and the lungs accumulate surfactant. In addition, the child begins to produce a special hormone that promotes the appearance of estrogen in the mother’s body, which activates the process of milk production for feeding.

On the head, the baby's hair becomes thicker, but still retains softness.

Thirty-third week (225-231 days)

The lungs are fully formed and in case of early birth at this stage the baby will be able to breathe without assistance. He weighs approximately 2 kg and is 43-44 cm tall.

All parts of the body become more proportional in relation to each other, and systems and organs continue to improve (for example, the mass of the heart increases and the tone of blood vessels increases). The position of the baby's body is fixed in the uterus (he can turn his head or butt down), usually after that he will no longer turn over.

Thirty-fourth week (232-238 days)

The baby’s body weight has already reached 2-2.5 kg, and the body length is at the level of 44-45 cm. Despite the fact that he is practically no different from a newborn, the body is still continuing to improve all its parts.

Cranial bones remain just as soft and mobile, which is necessary for unhindered passage of the birth canal at birth. Increased hair growth begins on the head and it can even change color.
Also worth noting intensive bone strengthening, for which the fetus is forced to take calcium from the mother’s body. Constant swallowing of amniotic fluid by a child stimulates the functioning of the kidneys and gastrointestinal tract.

Thirty-fifth week (239-245 days)

The baby gains 25-35 g daily, which is why the weight can vary significantly and by the end of the week it will be 2200-2700 g (with a height of 46 cm). All internal organs continue to develop, and fatty tissue still accumulates, thanks to which the child becomes well-fed.

There is already a fairly large amount in the fetal intestine meconium, which usually goes away 6-7 hours after birth. The baby is actively training to suck the mother's breast - he sucks fingers (even on his feet) and swallows amniotic fluid.

Thirty-sixth week (246-252 days)

Weight and height The already almost fully formed child is now very different and can range from 2 to 3 kg and from 46 to 48 cm. The adipose tissue is already quite well developed, the skin color acquires a light shade, and wrinkles and folds completely disappear.

Unlike other bones, the cranial bones remain just as soft and have so-called movable "fontanelles". All organs and systems completely ready for his work in the big world.

Thirty-seventh week (254-259 days)

The fruit reaches 48-49 cm in length, and its weight is within 3 kg, with a possible slight deviation from this value. The skin has already brightened well and thickened, and the fat layer increases daily by 14-15 g per day.
The cartilages of the ears and nose become denser and more elastic, maturation ends lungs and digestive system. From this moment on, even if labor begins, it will no longer be considered premature.

Thirty-eighth week (260-266 days)

It is likely that at this stage your baby will be born, but even if this does not happen, then it’s okay if he grows a little more in the womb.

No special processes at 38 weeks already not happening, baby only gaining weight. All his organs and systems are already fully developed and fully functioning.

Thirty-ninth week (267-273 days)

Normally, two weeks before the expected due date, baby starts to go down, increasingly pressing against the bones of the pelvis. It is already fully matured and the placenta begins to gradually age, as a result of which all metabolic processes in it significantly deteriorate.
Baby's weight increases daily by 30-35 g per day, which is accompanied by a complete change in the proportions of his body: the shoulder girdle and chest are already well developed, the tummy is rounded and the limbs have become longer.

Ongoing development of the child's central nervous system, although this process will continue after his birth. During this period, amniotic fluid is renewed every 3 hours, although its total amount is significantly reduced.

Fortieth week (274-280 days)

The fortieth week is considered last stage of pregnancy, but in fact, the child may appear either earlier or later than the due date.
At that time all indicators of its development fully correspond to the characteristics of a newborn baby. Body weight ranges from 2.5 to 4 kg or even higher, and height averages 49-52 cm.

There are intermittent contractions of the uterus, which the woman feels as episodic nagging pain in the lower part. The baby's skull bones are still soft and pliable.
Having gone through all stages of its development, a little man appears in front of you, very similar to his parents, but how he grows up depends only on you.

The intrauterine development of a baby is an amazing process. In just 9 calendar months, the baby goes through the entire path of human evolution, which took humanity hundreds of thousands of years. Expectant mothers, regardless of what kind of pregnancy has occurred, are always interested in knowing what the baby is doing and how the baby feels in the womb.

Our article offers a detailed description of fetal development by week of pregnancy.

Enter the first day of your last menstrual period

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general information

Pregnancy is a magical time, a woman is preparing to become a mother and does not even imagine the entire global scale of the processes that take place inside her body.

From the moment of conception, when two sex cells merge - male and female, a lot is already predetermined. At this moment, the sex of the baby is determined (the fusion of chromosomes according to type XX guarantees the development of a girl, and XY - a boy). At this moment, it is absolutely known exactly who he will look like, what kind of eyes and hair he will have, height, talents and abilities, what hereditary diseases may appear in the child. Only a woman does not know all this; nature knows this.

Pregnancy lasts on average 40 obstetric weeks. Fetal weeks are the time that the baby actually exists (from the moment of conception), and obstetric weeks are considered to be the time from the first day of the last menstruation in the conception cycle.

All calculations that are carried out while expecting a baby are indicated in obstetric weeks. Ultrasound specialists have compiled tables based on them; based on these dates, they will be guided by the correct formation of the fetus and assess how it grows and develops.

At 40 weeks exactly no more than 5% of babies are born, the rest of the births occur between 38 and 42 weeks. The birth of a child before the 37th week (inclusive) is considered premature, before the 22nd week - a miscarriage.

Intrauterine development is divided into periods and stages. When the fertilized egg is just preparing to implant itself into the wall of the uterus, it is said that the pre-implantation period is underway. After implantation, the embryonic period begins, which lasts 8 weeks; from the 10th obstetric week, the fetal period begins. In the embryonic stage all organs and systems are formed; in the fetal stage they only grow and increase in size.

The factors influencing the development of the fetus are multifaceted: these are the woman’s health, and the heredity of the parents, and bad habits (smoking, alcohol), and the state of the environment in the area where the expectant mother lives, and her social status (nutrition, availability of vitamins), and the availability of medical care. help and much more.

Please note that the weekly development of the baby is presented in obstetric weeks.

Development in the first trimester

First

There is no baby yet. Not at all. The woman has started her period and may not even be planning a pregnancy yet. The body is in the process of cleansing the uterine cavity from the endometrium that grew in the previous menstrual cycle. By the end of the week, menstruation ends, changes begin to occur at the hormonal level - follicle-stimulating hormones are produced, and the luteal phase begins.

Second

In the ovaries, under the influence of hormones, follicles mature. By the end of the week, one of them will burst and release a mature and ready-for-fertilization egg into the wide part of the fallopian tube on the right or left. She lives for about a day. It is on these days that she will meet the sperm.

During conception, cells fuse and their DNA begins to create a new full-fledged cell. It is unique; there has never been another like it in the world. It contains all the information about the unborn child.

The fertilized egg, moved by the villi inside the fallopian tubes, begins to gradually move down into the uterine cavity. The woman’s body begins to actively produce progesterone. It prepares the inner layer of the reproductive organ, builds it up so that the embryo can attach. The baby is called a zygote. The zygote is constantly fragmented.

Third

3-6 days after ovulation, the zygote ceases to be such and becomes a blastocyst. It enters the uterine cavity and still floats freely in it, not being attached to the uterine wall. The blastocyst has two layers: the inner one will later become the internal organs of the child, and the outer one has to manifest itself now - it is responsible for the implantation process. If the attachment process does not take place or does not take place correctly, pregnancy will not develop.

Approximately on days 7-9, the blastocyst adheres to the wall of the uterus, but later implantation also occurs. The most important process lasts about 40 hours. After the blastocyst has adhered, its gradual immersion into the endometrium begins. The villi of the outer layer produce a special enzyme that dissolves endometrial cells. The blastocyst is actually “buried” in it.

When the fertilized egg sinks into the endometrial layer, the villi of the outer layer of the blastocyst connect with the woman’s blood vessels, and the embryo begins to feed - receive everything it needs for development from the mother’s blood.

Fourth

The woman has not yet experienced a delay, but the baby blastocyst has already become an embryo and acquired its first characteristics: its weight is about 0.5 grams, its height is less than 1 millimeter. Three embryonic petals are formed. The outer one will later become the skin of the child, the middle one will form the basis for the gradual formation of the heart and blood vessels, genital organs, bones and muscle tissue, and the inner one will be the organs of digestion, respiration and the genitourinary system.

The rudiment of the spinal cord appears. All other organs exist in the same state of prototypes. They are still groups of cells similar in purpose, but within a few days internal organs will begin to form from them. The baby himself looks like a ball. At this time, he can be congratulated on his first independent achievement: he learned to extract oxygen from maternal blood with the help of chorion.

Fifth

It's time to please mom. It's time to take a pregnancy test. The delay has begun Some women may already feel the first signs of pregnancy, but this is not necessary.

Things are going better for the embryo - this week his heart will start beating. While it is two-chambered, the process of formation of sections is still ongoing, but by the end of the 5th week it will begin to contract rhythmically. It is at the end of this week that you can see and hear the baby’s heartbeat for the first time on an ultrasound., if it is carried out with a vaginal sensor.

Cell division and organ formation continue. The growth of the embryo this week is already about 1.5 millimeters, weight is within 1 gram. Sex cells begin to develop.

This week is considered one of the most important, since now the child is developing the prototype of the nervous system - the tube that will become the brain and spinal cord. The steps in this process are very complex.

Sixth

Many people are going for an ultrasound this week to confirm their pregnancy test data. But, apart from the fertilized egg in the uterus, the doctor will see little yet, because the embryo is still very small. But compared to the previous week, it almost doubled. Its height is about 3.5-4 mm, weight is about 1.5 grams.

At this stage, the child’s immune system begins to form – the thymus gland is formed. The heart is already beating, albeit unevenly. The formation of the arms begins, dark dots-protrusions appear in the place where the eyes would be, and small dimples appear where the ears should be. The little one can’t move yet, but it will only take him about a week to master this skill.

Seventh

The baby has doubled his height again and is now about 5-7 millimeters. Weight – 1.5 grams. Now it can be assessed using a visual and favorite method for pregnant women - in comparison with fruits and vegetables. At 7 obstetric weeks, the baby reaches the size of a white bean grain.

During this period, nerve fibers are being formed; this is a very important process. How the tiny person’s body will work depends on it. By the end of the 7th week, the baby gains the ability to move, but for now he moves reflexively, as new nerve fibers form. The formation of the organs of vision begins, therefore at 7 weeks it is important for a woman to consume enough vitamin A and folic acid.

The single intestine is divided into sections, which will later become the esophagus, stomach, and pharynx. And this week the new pancreas begins to produce the first insulin. The only respiratory organ is the trachea. The heart becomes four-chambered and completely takes over pumping blood throughout the body of the embryo. Gender is not yet obvious: both boys and girls have only identical-looking genital tubercles where the genital organs are to develop.

The embryo does not yet look at all like a person, but the accumulation of cells also no longer resembles it; now it looks like an alien creature with widely spaced dark dots like eyes and a gigantic head in relation to the body. There are no fingers, there are some fins at the end of the forelimbs. There's still a tail. The baby learned to bend and unbend.

The primary placenta appears, no more than 1 centimeter thick. The formation of uteroplacental blood flow begins.

Eighth

The week is held under the motto “Everything for the nervous system!” Its formation is now the most significant and important process. And it goes very quickly. The brain has separated from the spinal cord and the cerebellum begins to appear. The baby gets the opportunity to move his head.

The woman’s feelings have already changed; it is possible that after the appearance of the placenta, she will experience all the “delights” of toxicosis in the early stages. You don't have long to wait - at the end of the first trimester, the discomfort should decrease and then disappear completely.

The baby's height exceeds 2.5 centimeters and this is a real breakthrough. It is similar in size to a small grape. Facial structures continue to form. The baby's external genitalia begin to form under the influence of the mother's hormones, but it is still impossible to determine the gender.

Ninth

The similarity between the embryo and a person is increasingly noticeable - all parts of the body have formed. The laying of organs is completed, growth begins. In a few days, the baby will no longer be called an embryo and will become a fetus. The baby's head is pressed to the chest, but the tail has shrunk, now it looks more and more like a human tailbone.

The baby’s main achievement now is the ability to open and close his mouth, he has already learned this. The formation of future teeth inside the jaws begins. Along with the cerebellum, the pituitary gland appears in the brain. Cranial and spinal nerves are formed. This gives the baby a new skill - the ability to clench and unclench his fists.

The liver begins to work, the first own lymphocytes appear, the work of the kidneys and thyroid gland begins. But the main thing is that this week the placenta begins to work in full force. Now she not only “feeds” the baby, but also protects him and serves as a barrier.

The size of the baby resembles a large grape - height up to 5.5 centimeters, and weight - about 5 grams. The diameter of the fertilized egg is about 35 mm.

Tenth

The embryonic period of development has ended and the fetal period has begun. The baby is called a fetus and will remain so until birth. Outwardly, he already looks like a person - there is no longer a tail, there are four limbs, a tailbone, and a head.

The baby's weight is about 10 grams, height is from 6 to 7 mm. In size it resembles a decent-sized bead or a small plum. The development and branching of the nervous system continues.

The brain has two hemispheres. Movements are not yet controlled by the brain, but everything is moving towards this - the formation of the first neural connections begins. By the end of the week, the baby begins to bring his hands to his mouth and touch his face. Organogenesis is fully completed, now the organs just have to grow. The kidneys are actively producing urine, the baby swallows water and pees, the water is renewed every 3.5-4 hours. The head is rounded, but still remains very large in relation to the body. Lips and eyelids appeared, the nose and ears were blocked. Now the baby has a neck, and he begins to turn his head.

At the current stage, you can congratulate the baby on the fact that his first hair begins to grow, thin skin begins to feel the first tactile sensations.

The arms are longer than the legs, there are small nails on the fingertips, and the joints (elbows and knees) work. From this week, the process of mineralization of bones begins, until they more closely resemble cartilage. Also at this time the diaphragm appears. The baby is free in the uterus, he swims and constantly turns over. At the end of the 10th week, the baby begins to distinguish (so far only very conditionally) taste - taste buds are formed on the tongue.

Eleventh

The dangerous period has practically passed. Internal organs “rehearse” interaction. The baby's growth slows down somewhat with the end of the embryonic period, but the weight gain with each subsequent week will be more and more significant. The child weighs more than 15 grams, his height is about 8 centimeters. In size it resembles an average pear. Already now, if the baby is ahead of the fetometric norms, there is reason to assume a tendency towards a large fetus.

The anatomy of the fetus is perfect, everything is there, but only very small and functionally immature. At this stage, the baby will have to master one of the first reflexes - grasping. Now he has more fun, he can grab the umbilical cord and his own legs.

The head visually becomes slightly smaller. If earlier it accounted for two-thirds of the total volume of the body, now it is only half. The eyes have almost completed their journey from the side surfaces of the head (like a fish) to the center of the face and at this time occupy almost the correct anatomical place. The formation of the retina, iris, lens and cornea is actively underway. The bones begin to accumulate calcium; a pregnant woman’s diet should be tailored to take into account the increased need for it.

This week you can congratulate your little one for her newfound ability to push off an obstacle with her feet. If the baby swims to the wall of the uterus, he now pushes off and swims in the opposite direction. But these tremors are still very light, the woman does not feel them. There is one more reason to be happy for the baby - he learned to yawn.

Twelfth

Your baby is exactly 10 weeks with you (family holiday dinner idea!). Its height reaches 9-10 centimeters, and its weight is approximately 20 grams.. These parameters are comparable to a medium-sized lemon. The body is still disproportionate - the head is large, and the legs remain shorter than the arms. But g the holes are completely in place, which immediately gave the child a completely human appearance. The formation of the eyelids has completed, but the baby cannot open his eyes yet.

The earlobes are growing and the lobes are appearing this week. The nose also begins to grow actively. Now, even in a blurry, poor-quality ultrasound image, the relief of the face is visible, and those with large noses already differ in appearance from their snub-nosed peers. The spinal cord, which was in charge of nerve impulses, begins to transfer powers to the brain.

The baby has mastered the sucking reflex. He perfectly distinguishes flavors - he already likes the amniotic fluid after eating chocolate much more than after eating garlic.

The intestine, the formation of which is completed, begins to master the first muscle contractions, which will become peristalsis. Boys will have a penis this week, and girls will have labia, but the organs are still small, and it is not always possible to determine the sex of the child on an ultrasound. To avoid confusion, it is better to ask the doctor this question later.

Periods of sleep are replaced by periods of activity, muscles grow, and therefore the baby actively moves (even in his sleep), he already knows how to suck his finger. Mimic movements appear - he folds his lips into a tube and frowns. From this week the child begins to empathize with his mother: if she is worried, his heartbeat quickens, if she is calm, the baby is also calm. Experts cannot explain this connection, but there is an assumption that stress hormones are to blame.

Thirteenth

The baby is gaining weight almost daily. Now in size it resembles a solid onion, his height is about 11 centimeters, weight is about 30 grams. The little one makes a depressing impression - he is very thin, covered with wrinkles, like an old man, and all bright red. And all because he does not yet have subcutaneous fatty tissue, and all the blood vessels are visible through the thinnest skin.

The head is in no hurry to acquire normal proportions and still remains large. The arms are longer than the legs, but the legs also begin to actively grow from this week, and soon the disproportion will be eliminated. The thigh length this week averages 8.5 mm. The formation of the middle ear has completed, but the process continues in the outer and inner ear, and therefore the baby begins to hear, but so far only perceives sound as vibration of waves. This is how, by the way, all reptiles hear. This will continue for about two more months, until the mature structures of the brain allow sounds to transform into normal and familiar sounds to our ears.

The brain matter is actively growing in the brain; every day there are 250 thousand more new cells in it. The baby learned to shudder and hug his shoulders. In girls, the ovaries descend into the pelvis, and now they contain about two million eggs. This is a personal record for every lady, since then the number of oocytes will gradually decrease. Ovarian reserve is limited.

Little boys cannot yet boast of the descent of the gonads into the scrotum; this will happen before childbirth, but at this time their prostate gland is formed. Mineralization of bones is in full swing: the skull and spine harden first, and only then the limbs. Baby is getting ribs this week. All organs of the respiratory system are formed, and the chest begins to expand. Vocal cords are formed.

Development in the second trimester

Fourteenth

The baby's height is now 12-14 centimeters, and his weight reaches 50 grams. In size it resembles a small pomegranate. While all the internal reserves of a small organism are devoted to the development of the nervous system, the growth of bones and muscle tissue, the process of weight gain will begin later. Many babies have decent-sized hair on their heads, but so far all babies are natural blondes - the pigment that colors the hair has not yet been produced.

At this stage of the intrauterine journey, the baby can be congratulated for the fact that he has fingerprints. The pattern on the pads is unique, it is unique to him alone in the whole world. The child’s eyes begin to distinguish between light and darkness; he is not yet capable of more. With a bright light directed directly at the abdomen, the baby's movements become more active.

The spinal cord relinquishes its role in regulating nerve impulses and begins producing blood cells. The brain is mature enough to take control of organs and systems.

The baby’s heart pumps up to 25 liters of blood per day. This week the baby learned to smile, albeit unconsciously, reflexively. In the same way, he will give a dazzling toothless smile during the newborn period.

Fifteenth

The baby is getting bigger. Its size is comparable to an apple - height is 16 centimeters, and weight is about 100 grams. The baby's skin is covered with thick vernix lubricant, which performs protective functions. To prevent it from being washed away by amniotic fluid, it is held in place by lanugo - thin, colorless hairs on the skin.

The first convolutions appear on the brain, and the baby noticeably “gets smarter.” The cerebellum already better coordinates the movements of the limbs. Dark green original feces, called meconium, begin to be deposited in the intestines; this is what the baby will empty in the first days after birth.

Boys begin to produce their own testosterone, girls do not yet produce their own sex hormones, and are content with their mother’s. The volume of amniotic fluid is increasing and this is the norm.

Sixteenth

Gradually the baby gains weight, and now weighs up to 130 grams. Baby's height is 17 centimeters, in size it resembles a large avocado fruit and could easily fit in the palm of an adult. The neck has completed its formation, now the fetus is able to hold its head straight and not pressed to the chest. The muscles responsible for eye movements began to work. Under the eyelids, the baby begins to quickly move his eyeballs in his sleep. Eyelashes appeared. The forehead begins to protrude forward, which makes the baby more and more human-like.

The formation of the muscle frame has been completed, now all the muscles are just growing. Facial muscles are better developed than others - the baby knows several dozen different grimaces. The child begins to distinguish high-frequency vibrations of sounds: the sound of a doorbell from an alarm clock, father's voice from mother's. This week the endocrine glands begin to work fully. The length of the umbilical cord reaches half a meter.

This week you can congratulate the baby on the fact that he is beginning to produce his own hemoglobin, and his parents on the fact that the sex of the baby is now accurately determined by ultrasound. And another curious feature of this period is that the baby learned to spit and hiccup.

Seventeenth

This week is notable for the fact that for the first time the size of the baby exceeds the size of the placenta - The baby weighs about 160 grams, and his height reaches 19-20 centimeters. It is similar in size to a newborn puppy. This week, subcutaneous fat begins to be produced, now the baby’s weight gain will be more intense, along with this, thinness will disappear and nice roundness will appear.

The baby already looks like one of the parents, he has all his facial features formed. The outer ear has been formed, but subtle and delicate processes in the inner ear are still ongoing. The world of sounds for the baby becomes more diverse: the first transformation of sound waves begins, and therefore the baby no longer begins at the level of high-frequency vibration, but almost like you and me, to perceive loud sounds and the beating of the mother’s heart.

It is believed that this week the baby begins to dream. The nervous system is so developed that the baby has the opportunity to coordinate simple and combined movements. This means that he can suck a fist not because it happened that way, but because he wants it.

The instinct of self-preservation appears– with a loud sound, the baby groups and contracts. You can now hear the heartbeat without an ultrasound, using the most ordinary phonendoscope at home. Now the baby sleeps less. Periods of wakefulness are filled with knowledge of the world - he feels himself and the space around him. This week, experienced mothers can already feel fetal movements.

Eighteenth

The baby now weighs up to 220 grams, his height is about 22 centimeters. Compared to vegetables and fruits, a child is comparable to a ripe mango. This week the growth of the head slows down, while all other parts of the body do not slow down. This is important so that there is no disproportion.

The cerebral cortex is formed very intensively. The process of mineralization of the skull bones and large paired bones has been completed. For the first time in its entire intrauterine history, the child’s legs exceeded the length of his arms. The child swallows up to 400 ml of amniotic fluid per day. This is how he trains his digestive system and urine excretory organs.

Nineteenth

Now the baby will not grow as fast as before. But every day you will gain weight. Now his height is about 24 centimeters, and his weight is about 300 grams. It resembles a large tomato. The skin begins to smooth out, but so far the changes are minimal - not much subcutaneous fat has formed. First of all, it is deposited in the neck, shoulder blades and lower back. Eyebrows and eyelashes are formed. The baby has been moving for a long time, but right now he has reached a size at which a woman can begin to feel him. Multiparous women, at least at the current stage, almost always feel when the baby begins to push.

This week you can congratulate your baby on gaining full hearing.. Now he begins to perceive sound waves, like you and me, but he hears mainly what is happening inside the mother - how her heart beats, her intestines work. Only the mother's voice and loud sounds from outside reach through the strong abdominal wall and the layer of amniotic fluid.

Twentieth

This period is the middle of pregnancy, half of the journey has been completed. The baby has achieved a lot in development. Now its size is comparable to papaya: height – about 26 centimeters, weight – 350 grams. He is no longer as thin as he was a couple of weeks ago, but he is not yet handsome: his cheeks have already appeared, but his arms and legs remain thin and thin.

This week the skin becomes four-layered.

This week the baby begins to make his first attempts to open his eyes. The blink reflex is formed. From this time the immune system begins to work in full force.

Now it becomes obvious whether the child is right-handed or left-handed. Seven out of ten babies suck their right thumb, and it is the right side that will be predominant for them. This week, the vast majority of women pregnant for the first time begin to feel a weak, barely perceptible push from within.

Twenty-one

The baby is getting better. His weight is already more than 400 grams, and height can reach 28 centimeters. In size it can be compared to a doll. The baby's skin is no longer bright red and purple. The first layer of subcutaneous fat, although it is still thin, transforms the appearance of the baby. The formation of fat is of great importance for the survival of the child, it helps to maintain internal heat. Heat loss due to a small amount of subcutaneous fat is one of the main causes of death in premature infants.

The share of the head in the proportions of the body is now allocated about a quarter. By birth, the head will make up only a fifth of the baby’s total body volume. A belly appeared. The baby is looking more and more like a newborn.

The nervous system develops without breaks or days off; thousands of new neuron cells appear every second. Grooves and convolutions are actively formed in the brain. Reflexes develop and sharpen. A center develops in the brain, which will then be responsible for recognizing speech and native language.

This week your baby can be congratulated on the fact that he has an idea of ​​​​the change of night and day, and a semblance of his own routine appears. He may still be different from his mother’s, but gradually their regimes will begin to coincide.

Twenty-second

Childbirth that occurs this week (this happens) is no longer considered a miscarriage. They qualify as premature birth. And the baby has a chance of survival outside the mother's womb. The child's weight is more than 500 grams, height - 30 centimeters. The size is comparable to an ear of corn.

The baby already looks like a newborn. This week, fatty fiber begins to be distributed throughout the body, and the formation of the spine is completed. Lung maturation begins. A child’s understanding of the world is not limited to what happens in the womb. He becomes more emotional: he reacts calmly to stroking and his mother’s quiet voice, and worries and worries if he hears too loud sounds on the other side of the abdominal wall.

Twenty-third

The baby's growth remains almost the same, it has slowed down - just over 30 centimeters. The weight is increasing - now the fetus weighs an average of 560-580 grams. Hereditary factors begin to affect height and weight (short parents - small child, tall parents - large baby).

There are fewer and fewer folds and wrinkles on the child’s skin. There are none on the face at all. The least subcutaneous fat is on the ribs, the arches of which are clearly visible through the skin. The grasping reflex becomes local, that is, the baby can intentionally grab something with his hand. A respiratory reflex is formed - the lungs make special reflex movements. This reflex will come in handy later when the baby starts breathing air.

The sweat and sebaceous glands are active. The child already has his favorite and least favorite sounds.

Twenty-four

Children begin to kick more actively, and this pushing no longer raises doubts among expectant mothers. The height and weight indicators of children begin to differ noticeably, taking into account individual characteristics, and it becomes increasingly difficult to compare them with the norm. And the norm is: height – 31 centimeters, weight – about 600 grams.

This week, the baby begins to gradually get rid of lanugo hair on his body. They fall out, and this process should be completed by childbirth. If part of the lanugo remains, the hair will fall out in the first weeks of a newborn's life without any treatment. Tendon reflexes appear.

Twenty-fifth

A qualitatively new period begins - the baby will have to begin learning to survive, because the environment outside the mother’s belly is very different from the intrauterine one. The baby's height is about 33-35 centimeters, weight is about 700-800 grams. The child no longer looks like a wrinkled dried fruit, the skin is almost smoothed out.

The production of melanin begins, causing the skin to become pinkish. The ears remain soft, the degree of maturity of the lungs is low. If the baby is born, he will be severely premature, but he has a chance of survival. The lungs begin to produce a special substance called surfactant. It will help the alveoli not to stick together during spontaneous breathing.

According to WHO, the fetus is considered viable. The chances of survival are on average estimated at 15-17%. The child alternates between fast and slow sleep phases, with REM sleep predominating.

Twenty-sixth

This week is the last week in the second trimester, and most babies take the correct position in the uterus - head down. But if the baby is not positioned correctly, then there is still time to roll over. The baby's weight is from 800 to 850 grams, height is more than 35 centimeters. The baby's ears are still soft and protrude slightly; as the cartilage tissue hardens, they will return to their normal position.

The amount of cheese-like lubricant on the baby’s body and face decreases. The formation of receptors that will be responsible for the sense of smell is underway. The fetus sleeps up to 23 hours a day, that is, almost constantly.

The brain establishes a connection with the adrenal cortex, and the child develops its own hormonal background. The pituitary gland begins to produce growth hormones. For most boys, the testicles descend from the abdomen into the scrotum this week.. The viability of children born at this stage increases to 30-35%, although the degree of maturity of the lungs is still insufficient.

Development in the third trimester

Twenty-seventh

The baby's height reaches 36-37 centimeters, weight varies from 900 to 1100 grams. The baby no longer fits in the uterus at full height and begins to take a so-called flexion position. It is now difficult to determine the sex of the child if this has not been done before - the genitals are covered.

Vision improves, now the baby can distinguish not only light and darkness, but also defocused color spots of different intensities. The accumulation of surfactant in the lung tissue continues. Survival rate increases noticeably - up to 75% of babies born at 27 weeks survive.

Twenty-eighth

Nothing new is formed in the child’s body at this stage, everything is formed and the physiological aspects are only being adjusted. From this week the perinatal period of pregnancy (peripartum) begins. The baby's height is 37-38 centimeters, weight varies from 1200 to 1400 grams. There are differences in weight between boys and girls: boys weigh 100-200 grams more.

Eyelashes become longer and cheeks become plumper. Gradually the butt appears. While everyone's eyes are blue, the iris will change a little later. The eyebrows no longer hang menacingly over the eye sockets, since the amount of cheese-like lubricant on them has significantly decreased. About 10% of the lanugo has already fallen out.

The optic nerve begins to work - the baby winces if the light falls on the stomach too bright. In the lungs, the formation of alveoli is completed, and the accumulation of surfactant continues. If born this week, up to 90% of babies survive.

Twenty-ninth

The baby is very large - his weight can reach 1.5 kilograms, and his height is 37-39 centimeters. The amount of subcutaneous fat has “grown” to 5% of the total body weight. The baby is fluent in more than a dozen reflexes. The formation of the cerebral cortex is completed.

The kidneys produce up to half a liter of urine per day. According to WHO, among those born at 29 weeks, up to 97% of children survive.

Thirtieth

A woman goes on maternity leave. Her baby looks almost like a newborn. Nine out of ten babies already occupy the correct head position in the womb; if not, then the chances of turning around are extremely low - the womb has become very crowded. The child’s height is more than 41 centimeters, weight is more than 1600 grams. The parameters can be compared to a melon.

Children who are destined to be brunettes begin to have darker hair on their heads. Body proportions have noticeably improved. The differentiation of the cerebral cortex is completed. Electrical potentials of the brain are recorded if desired.

Thirty-one

Well, the time has come when nothing else will change in the child’s body. He will only rapidly gain body weight, and this is his main task at the current stage. The babies' height now exceeds 41-42 centimeters, and their weight is approaching 1800-1900 grams.

The baby's skin turned pink, the folds were almost smoothed out. The baby no longer resembles a skinny poor fellow. Fatty tissue appeared under the skin of the extremities. The ears no longer stick out to the sides and are close to the head. The prognosis for viability, if the baby is born right now, is quite favorable.

Thirty-second

The baby takes up almost all the free space in the uterus. If he has not rolled over into a cephalic presentation, the chances of this happening are dwindling every day, there are almost none left.

The baby's height is more than 43 centimeters, weight is from 1700 to 2000 grams. The baby’s body begins the countdown: oxytocin is produced in small quantities, which should help the mother prepare for childbirth and form the so-called hormonal birth dominant.

Thirty-third

As it is now, the mother will see the child at the moment of his birth; in recent weeks he has only been gaining weight, everything else has been formed, and the child’s body is working at full capacity. The baby's height reaches 44-45 centimeters, weight is more than 2 kilograms. You can no longer admire the baby in full growth on an ultrasound; you can only examine the baby in parts.

The motor activity of the fetus decreases. It becomes difficult and cramped for him to actively move in the uterus.

With a three-dimensional or four-dimensional ultrasound, right now you can see, record and save the baby’s stunning, rich facial expressions for the family archive.

Thirty-fourth

The baby has grown to 45 centimeters and already weighs from 2200 to 2500 grams. Therefore, childbirth, if it happens now, should not be frightening, children survive well, the risks are minimal.

The placenta has reached the peak of its development, now gradual degenerative processes begin in it - it is aging. But this process is compensated, and it will not cause a deterioration in the baby’s condition.

The aging placenta begins to stimulate the production of prolactin, which prepares the woman for breastfeeding. Except for the baby's weight, everything remains unchanged.

Thirty-fifth

Now almost everything that a woman gains in weight will be due to the weight of the baby - he gains 200-300 grams per week. The baby's height this week is 45-47 centimeters, its weight can be either 2400 or 2900, it all depends on individual characteristics. Outwardly, the baby looks quite ready for birth, but the last month of pregnancy is very important, because the accumulation of surfactant in the lung tissue continues.

Skin folds and wrinkles are completely smoothed out. The original lubricant has almost disappeared, a small amount of it remains only in the folds of the skin. The iris of the baby’s eyes becomes what it needs to be according to genetic inheritance, that is, brown-eyed babies become brown-eyed, and not blue-eyed, as they were before.

Body proportions have finally become normal and harmonious– the head accounts for only a fifth of the body volume. The process of myelination of nerve endings has been completed. The brain has noticeably increased in mass, and the convolutions have become deeper. The baby already has 70 reflexes.

Thirty-sixth

The baby's weight has reached 2700-3000 grams, although there are also miniature babies that weigh just over 2.5 kilograms. The average height of babies is from 46 to 49 centimeters. In the majority of first-time mothers, the babies sank down and the abdomen sank. Shifting the center of gravity makes life easier for a woman, it becomes easier to breathe, but the pressure of the head on the internal os increases. This way the baby helps to gradually prepare the cervix for childbirth.

The skin has become dense, it reliably protects the baby’s body. Lanugo disappeared as unnecessary, only in some babies residual effects persist until birth. The nails protruded beyond the phalanges for the first time. All bones are mineralized, only the bones of the skull remain mobile to facilitate the birth process. The centers of thinking and logic operate in the brain. The brain controls the functioning of all organs and systems.

There is less amniotic fluid, because the baby needs to free up at least a little space in the uterine cavity.

Childbirth at 36 weeks is not uncommon, you should not be afraid of it, although the baby is considered premature, it has everything necessary to survive and develop quite normally.

Thirty-seventh

Now the baby is gaining about 50 grams per day. Average The weight of the fetus at this stage is 3100 grams. Height – 49-52 centimeters. The senses are being adjusted, the baby is preparing for birth, which will require enormous efforts and adaptive abilities from him.

Enough surfactant has accumulated in the lungs, necessary for full breathing, and now the production of this substance slows down somewhat, but does not stop completely. In case of childbirth, the prognosis is positive, since prematurity will be mild and does not require resuscitation.

Thirty-eighth

According to statistics, every third birth occurs this week. They can happen at any minute and this should not be scary - the baby is ready. The average weight at this stage is 3300-3600 grams, height is 50-52 centimeters.

The baby's skin is pink and smooth, he has accumulated enough subcutaneous fat. Almost all boys have testicles that have descended into the scrotum. In 2% of children they will still have time to go down. Due to the maternal level of estrogen, the external genitalia in children of both sexes are slightly enlarged, and swelling is also characteristic of children's mammary glands.

The work of all internal organs is coordinated with each other. Only the lungs are not working yet; their time will come immediately after the baby is born. Kids are very emotional; they can experience fear and joy. The number of movements has noticeably decreased, but the kicks and pushes have become painful, because the water has become scarce.

Thirty-ninth

There is very little left. Soon the mother will be able to see the baby. The baby’s weight is almost the same as it will be at birth: there are little ones that weigh only 2900-3000 grams, and there are big ones - over 4 kilograms. Height is more than 53 centimeters.

If the baby is not born this week, he will not gain much more - no more than 100 grams per week, since now the weight is growing more slowly.

The process of accumulation of surfactant in the lung tissue has almost completed. The lungs are ready for independent breathing. The nervous system is still being fine-tuned, but this process will continue after birth, throughout the first year of life. The child has his own daily routine, he sleeps and is awake at certain periods of time.

The baby's head is pressed to the exit of the uterus, the arms are folded on the chest. He is ready to be born. If the baby is in a breech or transverse presentation, then a planned caesarean section may be performed this week or the operation may be postponed a week in advance.

Fortieth

Your baby is perfectly developed and ready to meet this world. He doesn't have enough space in the uterus, and the baby's movements are difficult. All organs are formed. The cartilage tissue hardened, as did the bones of the skeleton. Only the bones of the skull remain free and mobile, but this is necessary in order to pass through the birth canal without injury.

Due to the discomfort that the child experiences due to the cramped conditions in the womb, he begins to produce a stress hormone - adrenaline. It also helps the mother’s body prepare for labor. Under its influence, the production of oxytocin increases, and the cervix opens faster. The placenta has the last, third degree of maturity. The baby may no longer have enough oxygen.

Labor may or may not begin this week: until 42 weeks, pregnancy is not considered post-term, so don’t panic or worry. In recent days, it is better to reduce the amount of calcium-containing foods in your diet so as not to cause early hardening of the skull bones, especially if pregnancy extends to 42 weeks.

With the onset of labor contractions, the cervix will begin to dilate, and when it is fully open, the baby will begin to move forward. His every movement and turn in the process of passing the birth canal will be a reflex (it’s not for nothing that the nervous system prepared for this so diligently and for a long time). The baby seems to know how and what to do at any given moment. This process is called the biomechanism of childbirth.

Throughout pregnancy, it is important for a woman to remain calm and not be nervous, since muscle tension, which is caused by stress and fear, is the main cause of labor pain and ruptures.

Prepare for the baby’s arrival with him and even take his example: the dynamics of his development over 9 months shows that he is not afraid, he is confident in himself and his mother.

During the period of bearing a child, a woman is constantly observed by a doctor.

This allows you to avoid unpleasant consequences and achieve a successful delivery. Despite the control of doctors, the expectant mother wants to know what is happening inside her body, how the fetus develops over the weeks of pregnancy, what sensations should arise and what the baby himself experiences. A gynecologist does not always have enough time to answer all questions, so a pregnant woman turns to the Internet.

Fetal development in the first trimester

The first trimester lasts approximately from conception until the 12th week of pregnancy. This period is considered the most responsible, since at this time the laying of organs occurs. There is no placenta in the full sense of the word yet, so a woman needs to be careful in using drugs, since they enter the embryo through the blood (up to 9 weeks the concept of “embryo” is accepted, then “fetus”) and can cause irreparable harm to it.

During the first 2 weeks after conception, the embryo implants in the uterus. At this time, a woman may not notice any changes at all, no weight gain occurs. Starting from the 3rd week of pregnancy, the embryo begins to actively grow and develop.

The development of the fetus occurs rapidly and largely depends on the state of the mother’s body.

3 weeks. The size of the fetus at this stage is no more than 2 mm. The formation of the neural tube, chord, and blood vessels are already beginning.

4 weeks. The size of the embryo doubles, it is already about 4 mm. It develops germ layers that will continue to develop, transforming into full-fledged tissues.

5 weeks. At this stage, the woman begins to suspect that she is pregnant. Her unborn child reaches 12 mm in length and weighs about 2 g. The formation of the brain and other internal organs occurs. There is no placenta yet, it is replaced by the chorion, a membrane covered with villi, which will then grow with vessels, capillaries and become the placenta.

6 weeks. The brain develops more intensively than other organs, so the head is still much larger than the body. The genitals are forming, but it is not yet possible to determine the sex. The nervous system improves, facial features begin to be defined.

7 weeks. By the beginning of the 7th week, the length of the fetus is already almost 2 cm. Its urinary system is formed, the fingers and toes are separated. An ultrasound can determine the heartbeat, which is normally no more than 160 beats per minute.

8-9 weeks. The embryo turns into a fetus, fat cells appear in it, a four-chambered heart is formed, the kidneys begin to work, secreting the first urinary fluid.

10-12 weeks. By the end of the first trimester, the fetus already has facial expressions, can actively move, breathe, and swallow amniotic fluid. The genitals are in their infancy.

At the end of the first trimester, a woman is prescribed screening and ultrasound. These procedures make it possible to identify pathologies in the development of pregnancy, if any. It is possible to determine gender at this time, but the likelihood of error is high.

Second trimester of pregnancy

The second trimester lasts until week 28. At this time, the fetus is actively increasing in size, and the woman’s belly is noticeably rounded. If there was a risk of miscarriage at the beginning of pregnancy, the risks usually decrease by the second trimester. Toxicosis also weakens at this time.

The description of fetal development at this time is of particular interest to expectant mothers, because they begin to feel the first movements of the child. If earlier the movements were imperceptible, now you can notice the tremors.

Every week the fetus becomes larger, its internal organs improve:

13-15 weeks. During this period, the fetus acquires its own red blood cells, which begin to circulate in the blood. The digestive system continues to form, and the baby is already making the first swallowing movements. The sucking reflex is activated, so on an ultrasound, the doctor may notice that the child is sucking his finger. The movements of the fetus become more active, it can turn over.

16-18 weeks. By the end of the 18th week, the genital organs are fully formed. The fetus not only moves itself, but also turns its head. He begins to blink, his facial expressions improve. The immune system is also developing, but before birth the child’s protective functions will completely depend on the mother.

19-20 weeks. The growth of the fetus at this stage is already more than 25 cm. The cerebral cortex is being formed, therefore during this period toxic effects (substances, nicotine, alcohol) significantly increase the risk of developing mental retardation in the child.

21-23 weeks. Starting from week 22, the fetus can survive outside the woman’s body. The lungs are already formed enough to breathe on their own. However, a child born at such a time will have many health problems.

24-26 weeks. The fetus is actively gaining weight. For this reason, the heart contracts more often, which is why they speak of physiological arrhythmia of the fetus.

27-28 weeks. By week 28, the centers of vision and hearing are formed. At birth at this stage, the baby begins to hear and see what is happening quite quickly.

You can learn from an obstetrician-gynecologist about how the fetus should develop over the weeks of pregnancy, a description of its appearance and the woman’s feelings. The second trimester is considered relatively calm for the mother. Various pathologies, including intrauterine death, are rare at this stage of pregnancy. Nevertheless, the woman is prescribed a series of tests to determine the development of the fetus and the condition of the expectant mother.

Baby in the third trimester of pregnancy

The final third trimester is full of anxiety for a woman. She is preparing for childbirth, preparing the house for the arrival of the child. And the child himself is preparing to be born.

It is believed that childbirth occurs at the 40th week of pregnancy, but even if a woman is nursing, this is considered normal until 42 weeks.

The child is becoming more and more like a newborn, his development is quite rapid:

29-30 weeks. The baby's taste buds have already been formed, so he begins to respond to his mother's nutrition. The taste of amniotic fluid depends on the foods eaten, which can cause approval or dissatisfaction of the baby. Baby teeth form inside the gums. Mature tear ducts allow the baby to cry. By the end of the 30th week, the baby should be in a position that will allow him to be born, that is, he turns his head down.

31-33 weeks. The formation of organs is completely completed at this time. The child's eyes begin to react to light, nails appear, and the skin takes on a pinkish tint. The child's immune system continues to develop.

34-36 weeks. Basically, at this stage, the child accumulates subcutaneous fat and gains weight. His cheeks appear. The movements become less active, as the baby becomes cramped in the mother’s belly, but he actively kicks, and the mother begins to distinguish between kicks and punches.

36-37 weeks. The baby already looks completely like a newborn and is ready to be born, but the heart valve has not yet closed. Weight at this stage usually reaches 3 kg. The placenta begins to gradually age, which is considered normal.

39-40 weeks. There are only a few days left before the birth. All organs and systems are formed, the lungs are completely ready for breathing.

If the pregnancy is terminated at this stage, the development of the fetus allows it to survive outside the mother's body. The chances of survival even at the beginning of the third trimester are very high.

By the time of birth, the baby should weigh 2500-4000 g. If the fetus is large enough, the question of a planned caesarean section is raised. Despite the fact that premature birth in the 3rd trimester is no longer so dangerous for the child, there is still a danger of fetal death and neurological problems, so doctors will try to stop labor before 36-37 weeks.

A woman’s feelings as the fetus develops

During pregnancy, a new organism grows and develops inside a woman’s body for 9 months. This cannot but affect her feelings. If this is the first pregnancy, many sensations are not yet familiar to the woman and can cause fright. All doubts and suspicions must be reported to your doctor.

The closer to childbirth, the more new emotions and physical sensations the expectant mother experiences.

Depending on how the pregnancy progresses week by week, fetal development and sensations will be constantly updated.

Since a trimester lasts 12-15 weeks, sensations during one trimester can constantly change, so it is better to talk about what a woman experiences each month of pregnancy:

1 month. At this time, the woman only finds out that she is pregnant or remains in the dark for some time. Signs of this condition may be completely absent, but some pregnant women note swelling and tenderness of the breasts, mild nausea, and nagging pain in the lower abdomen.

2 month. By the second month, a woman usually already knows that she is pregnant. Most pregnant women at this stage begin to experience severe toxicosis, nausea, vomiting, and food preferences change. Also, due to hormonal changes, a woman becomes sleepy and gets tired quickly.

3 month. The sensations from 2 months are not much different. Toxicosis may continue, and the breasts continue to grow and swell. The nipples become darker.

4 month. At the 4th month a small belly begins to appear. The abdominal and back muscles may ache a little due to sprained ligaments. Also at this stage, a woman faces such an unpleasant problem as constipation.

5 month. At the 5th month, a woman feels her baby moving. Since the uterus grows rapidly and puts pressure on the internal organs, heartburn may occur. The skin of the abdomen and thighs stretches and begins to itch.

6 month. The belly is growing quickly, and the back is starting to get tired. The first stretch marks may appear, so it is recommended to wear a bandage.

7 month. The woman begins to visit the toilet more often, and her back muscles hurt more. Insomnia appears. The baby's movements are so strong that they can cause discomfort to the mother.

8 month. Due to the weight gained, a woman quickly gets tired and finds it difficult to move. Sweating increases. The psychological state changes, the pregnant woman becomes more capricious, and anxiety states are possible.

9 month. The body is preparing for childbirth, so the stool becomes looser and more frequent, the intestines are emptied, and the woman loses a little weight. The stomach drops, so the urge to urinate becomes even more frequent.

Some pain during pregnancy is normal, as a woman's body is being rebuilt, but if the pain is too severe, you should immediately inform your doctor.

Possible deviations

Of course, a woman is not recommended to think about bad things during pregnancy. Stress and pessimism are bad companions of pregnancy. However, not everyone manages to remain calm. If there has already been a history of unsuccessful pregnancy, then the woman will try to find out as much as possible about what could go wrong.

Depending on how the pregnancy progresses, the development of the fetus and the woman’s sensations also gradually change. However, not all abnormalities can be noticed without examination, so all tests and ultrasounds should be done on time on the recommendation of a doctor.

Most often you can find the following fetal malformations:

Down syndrome. Despite the fact that older mothers are at risk, no one is immune from this pathology. This is a mutation that is associated with the appearance of an extra chromosome. It leads to dementia and stunted growth of the child. During the first screening at 12 weeks, it becomes clear whether there is a chance of having a baby with Down syndrome.

Patau syndrome. A severe chromosomal disease, which is also associated with gene mutation. The child has impaired mental development, possible deafness and many other pathologies. As a rule, children with Patau syndrome rarely live beyond the age of one year.

Heart defects. A heart defect in a child can also be detected during pregnancy. This pathology is very diverse. You can live with some defects for the rest of your life, while others are so severe that they are inoperable and incompatible with life.

Defects or absence of internal organs and body parts. The causes of this pathology are difficult to determine, but it is acquired and not related to genetics. The failure occurs at the stage of organ formation. Most often the brain and limbs are affected.

It is worth remembering that most pathologies and abnormalities in fetal development can be avoided. To do this, it is recommended that both parents undergo examination before conception, as well as be observed by a doctor and follow his recommendations.