A special organ that forms in the initial stages of pregnancy and eventually atrophies until the end of the third trimester is called the yolk sac. It resembles the shape of a ring and has thin walls. The size of the yolk sac from the fifth to the twelfth week should be 3-6 millimeters in diameter.

Yolk sac during pregnancy

This small organ plays a very important role in the development of the embryo:

• Its name suggests that it contains nutrients, which in turn are used in the initial stages of embryo development.
• During a pregnancy of three weeks, germ cells begin to form in the yolk sac, which then enter the rudimentary gonads of the embryo.
• The yolk sac is capable of producing the very first red blood cells, namely red blood cells, which are responsible for respiratory function.
• It is the yolk sac that is responsible for the transformation of substances that will then flow into the fetal liver.

Even these brief enumerations lead us to the idea that the role of the yolk sac is very important. It is very important to conduct an ultrasound examination in the early stages of pregnancy, with its help the doctor will be able to assess the condition of this formation.

Pathologies of the yolk sac

When examining the yolk sac, one may encounter the following phenomena: increased density of the yolk sac, its doubling or pathological change in shape, pathological size, and even the absence of this formation.

But the assessment of such pathological signs as a decrease or increase in the yolk sac is very subjective; it very much depends on the quality of the device and the qualifications of the doctor. Therefore, in such situations, you are usually advised to undergo repeated diagnostics in special centers, where the level of equipment and doctors is quite high.

If the yolk sac is not able to function normally, that is, it freezes, then spontaneous abortion, if the abortion does not occur, then there is a high probability of fetal pathology.

Undoubtedly the first Ultrasound For any woman, this is a very exciting stage during pregnancy. Right now she is beginning to worry about the health of her unborn child, his normal development. Naturally, if during the examination the doctor discovers some abnormalities, including the yolk sac, then the mother begins to worry. You should not draw premature conclusions; it would be better to calm down and discuss the possible consequences with your doctor. There are situations when neither the embryo nor the yolk sac are visible during an ultrasound. But the fertilized egg is still there. Unfortunately, this situation is a sign of a failed pregnancy. But there are also cases when the size of the yolk sac is much larger than usual. This is not a pathology, but it is imperative to monitor the progress of the situation.

The yolk sac is not visualized:

For example, ladies cite the results of an ultrasound, in which, for example, neither the embryo nor the yolk sac are visualized (that is, not visible). At the same time, the fertilized egg is present. Unfortunately, this situation is called “anembryony” - that is, the pregnancy did not take place.

The yolk sac is enlarged:

In other cases, on the contrary, it means that the yolk sac is larger than normal. The online consultant reassured the woman who came with a similar problem, explaining that this does not indicate any specific pathology and may be an individual feature. But, of course, it is necessary to control the development of the situation.

In general, every expectant mother should imagine what processes take place in her body at one or another stage of pregnancy or menstrual cycle. You should know how some medications, stress, and foods can affect the state of the reproductive system and fetus. Treat pathologies that may complicate pregnancy in a timely manner. But the most important thing is to find a specialist who will actually, and not formally, take responsibility for your health, bearing a child and a successful birth.

The conception and birth of a new living being is truly the greatest miracle in the world. Mammals have a yolk sac, fish have eggs, and reptiles and birds have eggs. All these elements allow such a unique action as the birth of a child to take place.

Evolution has brought many changes in the world of living beings. The methods of giving birth to babies were constantly changing. But each time, at a new stage in the development of the world, evolution made some kind of addition. With the advent of such a class of creatures as mammals, a new way of giving birth to children arose - viviparity. In this case, the embryo did not arise from an egg, as before, but developed and grew to a certain age in the womb of the mother. It was at this time that the yolk sac appeared.

general description

The yolk sac is perhaps the main organ in the life of a future person. It is he who appears in the embryo in the first stages of its existence. Scientists attribute it to the embryonic, or, in other words, to the larval, organs of the embryo.

The prototype of the sac can be considered the yolk of a bird or reptile egg. If you look closely at a chicken egg, you can divide it into two parts: the yolk and the white. It is a huge fertilized cell. The task of the yolk is to supply the embryo and future embryo with all the necessary nutrients, while the protein serves as a supply of water and essential amino acids; in the early stages, it protects the embryo from external irritants along with the shell.

In viviparous women, the embryo develops in a special organ - the uterus - and until the placenta is completely attached and the umbilical cord is formed, the embryo does not have the opportunity to feed with the mother. In this case, the yolk sac serves as a kind of digestive system and element for providing nutrition.

In mammals and humans at the embryonic stage, the yolk sac can be perceived as a kind of digestive system. It allows you to absorb nutrients that come to the embryo from the yolk, as well as transport the necessary compounds for growth and development through the bloodstream, thanks to a developed capillary system. In humans and many animals, during the process of evolution, the yolk sac lost its main function - digesting food for the embryo - and became an important organ for the formation of the circulatory system.

Human organ

After the embryo attaches to the walls of the uterus, its very rapid development begins. The growth of an embryo is a true miracle of nature. After birth, no creature is capable of developing as quickly as an embryo in the mother's womb.

Within a few weeks after conception, an endoblastic vesicle gradually forms at the site of the fused sperm and egg. He becomes a kind of “prototype” of the future human being. After a few more weeks, the yolk sac begins to form from the endoblastic vesicle. It will not last long - its “life” takes no more than three months, but without it the fetus will not be able to form normally.

The yolk sac is classified as a so-called provisional organ. They exist only temporarily. Their function is to replace for the embryo those organs that an adult has, but has not yet formed in the embryo. In addition to the yolk sac, the following provisional organs are known:

1. 1. Amnion, whose task is to form an aquatic environment in which a future person could fully develop.
2. 2. Chorion. This is practically the external organ of the embryo. Since the child must attach to the walls of the uterus, he needs to “bypass” its mucous protection, and the chorion helps the embryo in this.
3. 3. Placenta. This is an important provisional human organ. It is he who helps the future person breathe, eat, secrete waste products, grow and develop before birth. The placenta is a reliable protector of the child and accompanies him until birth.

The main task of the yolk sac in embryo development is the formation of the primary circulatory system and blood vessels. Already on the 15th day after conception, the gradual formation of the very first human capillaries begins in the walls of the organ. A month after fertilization, the yolk sac temporarily becomes the main reproductive organ of the embryo: on the 29th day of the embryo’s existence, the first cells are released that have an influence on the formation of the sex of the future person.

The yolk sac gradually lost its digestive function, which it was endowed with in birds, fish and reptiles. In the human body, it could become the prototype of not only the circulatory system, but also most organs.

Functions of the yolk sac

What is the yolk sac during pregnancy? In the first 3 months of embryo development, this is perhaps the most important organ. Starting from the 6th week and ending with the period of the first trimester, the yolk sac is able to replace most of the internal systems of an adult in the embryo.

What organs are the prototype of the yolk sac? Among them:

1. 1. Liver. At about 6 weeks it begins to produce alpha-fetoprotein, transferrins and alpha2-microglobulin. These proteins are vital for the normal growth and development of the embryo. The yolk sac is also called the primary human liver.
2. 2. Sexual. By the end of the first month of development, the first germ cells appear in the embryo’s body with the help of the sac. If a girl is formed, then it is at this time that her eggs also develop. During this period, any stress is dangerous for the expectant mother, since due to impaired fetal development, her daughter may become infertile.
3. 3. Kidneys and metabolic systems. One of the important functions of the yolk sac is excretory. At this time, it is a prototype of the kidneys, which function to cleanse the blood and remove excess fluid and dangerous toxins from the body.
4. 4. Immune system. It begins to form in the body of a future person quite early, but at the same time it is not able to withstand external threats. The yolk sac perfectly protects the embryo from any external attacks.
5. 5. Spleen. The organ allows the formation of macrophage cells in the body, whose task is to maintain “order” inside the small organism. In addition, do not forget about the main function of the yolk sac - the formation of blood cells and blood vessels.

At the end of the first trimester, when the fetus is 3 months old, all the main organs and systems are already present in its body. They allow the small embryo to function like an adult. At this time, the yolk sac is no longer necessary. After its expiration date, the organ begins to decline. Its size changes and decreases sharply. But it doesn't disappear completely. It becomes like a small cyst and is located at the base of the baby's umbilical cord throughout pregnancy until birth itself.

Developmental pathologies

The formation of the yolk sac is the most important stage in the growth of the embryo. Even minor disturbances in its development can lead to mutations in the fetus and even to a missed abortion. The doctor can detect any pathologies of the organ using an ultrasound examination. The first examination of a woman in order to establish conception should be carried out using an ultrasound machine. This allows you to assess the size, degree of development of the organ and its possible pathologies.

The following pathologies of the yolk sac exist:

1. 1. Impaired functioning. In this case, this provisional organ ceases to perform its main functions: it does not form blood, does not carry out metabolic and immunoprotective processes. Some time after the functioning of the organ is disrupted, the fetus dies and spontaneous abortion occurs. If an abortion does not occur, we can talk about a frozen pregnancy. If it continues to develop, the fetus may have a number of widespread pathologies that are incompatible with life. The causes of the condition may be chronic diseases of the mother or illnesses acquired during pregnancy, hormonal characteristics, severe stress, injuries, etc.
2. 2. Lack of visualization. After 6 weeks, the fetus becomes noticeable and can appear on ultrasound. 10 weeks after conception is the optimal time for an ultrasound examination. But in some cases, even after a fairly long period of time, the yolk sac may not be visualized. If the fertilized egg is in the uterus, and the organ and embryo are not completely visible, we can talk about the absence of pregnancy.
3. 3. The organ is larger than its statistical size. Enlargement of the sac cannot be attributed to pathologies of fetal development, but rather to developmental features. The size of the organ can be affected by the sexual health of the mother, her illnesses at the beginning of pregnancy, stress and physical fatigue, the use of certain medications, and even the ecology of the place of residence.
4. 4. Underdevelopment. Previously, such a pathology in most cases was fatal to the fetus or had detrimental consequences for its further healthy growth. Modern medicine provides special hormonal therapy. Underdevelopment of the yolk sac occurs due to a lack of progesterone in the body. Hormonal medications make up for this deficiency and allow pregnancy to proceed normally.

Diagnostics using an ultrasound machine

The most important ultrasound examination during pregnancy is the first one. It is carried out up to 12 weeks during the 1st trimester of a woman’s pregnancy. During this fetal ultrasound, it is impossible to determine the sex and possible size of the child at birth, but diagnosis at this particular time helps to learn about possible developmental abnormalities and dangerous genetic diseases.

Using ultrasound, a doctor can diagnose pathologies in the development of the yolk sac or disturbances in its functioning during a frozen pregnancy. At this time, it is necessary to have an abortion, since a fetus that has stopped developing poses a mortal danger to the mother.

The provisional organ is most noticeable by 6 weeks after conception. It is at this time that its parameters, in accordance with the size of the unborn child, are greatest. By 6 weeks, the size of the human organ reaches 5 mm. In the future, they may increase, but the yolk sac will not be noticeable as before, due to the sharp growth of the embryo itself.

During fetal development in the first trimester, the size of the provisional organ gradually decreases, which is clearly visible on an ultrasound examination of the fetal egg. After some time, the organ becomes like a kind of bubble. This suggests that the body of the future person no longer needs it.

By the 12th week of pregnancy, the pouch gradually begins to disappear, but does not disappear completely. It literally “retracts” into the child’s body cavity and becomes a small cyst. At the beginning of the second trimester, the size of the organ is so small that it is no longer possible to determine its position using ultrasound.

The disappearance of the yolk sac indicates that the embryo has carefully established itself in the mother’s body and carries out nutrition and respiration through the umbilical cord and placenta.

It is so established by Mother Nature that each organ performs its assigned function in the body. Gradually, with the development of science, humanity has studied every organ and its importance in our body. Only with the advent of ultrasound equipment did doctors have the opportunity to look into the secret world of the origin of life, but this only added new questions that needed answers. One of these mysteries was the then unknown organ, the yolk sac.

By order of the Ministry of Health of the Russian Federation, all pregnant women registered with antenatal clinics at their place of residence are required to undergo ultrasound screening three times at different stages of gestation:

1. 10-14 weeks;
2. 20-24 weeks;
3. 30-34 weeks.

The first ultrasound examination is carried out from 10 to 14 weeks. But for more accurate data, it is better to do an ultrasound at the end of the first trimester. During this period, it is easier to detect abnormalities in the development of the embryo, and in the case of serious defects, it is safer for the woman’s health to get rid of the abnormally developing fetus.

An ultrasound scan, which is performed before the first screening, is carried out only to establish pregnancy. And we are unable to detect any pathologies or abnormalities, because in a short period of time the size of the fertilized egg cannot allow this.

But the doctor may prescribe an ultrasound examination if necessary more than three times.

Examination with a device using ultrasonic waves is carried out in two ways: through the abdominal wall or through the vagina.

Ultrasound in the first trimester is assessed according to the following indicators:

1. Coccyx-parietal size. This is the size of the embryo from the crown to the tailbone. Every doctor has a table of the relationship between embryonic length and gestational age. KTE depends entirely on the period.
2. Heart rate. This criterion allows us to identify congenital pathologies of the cardiovascular system. The doctor also has a table of normative indications that can be used to determine early hypoxia and heart defects.
3. Thickness of the collar space. This is the length of the area between the skin of the embryo and the soft tissues of the cervical vertebrae. The indicator helps to identify terrible diseases such as Down syndrome. The nuchal translucency disappears after 14 weeks of conception.
4. Position of the chorion. Doctors call the placenta in the first trimester chorion. This standard indicates in which part of the uterus the fetus has taken its place.
5. Nose bone size. Like other criteria, the length of the nasal bone during screening will help identify abnormalities in the development of the baby. If ossification of the bridge of the nose is not detected or it is too small, then this indicates a chromosomal abnormality. If no other violations are found, then there is no reason to panic.
6. Yolk sac. This indicator is of particular importance as it helps to detect an undeveloped pregnancy. There is a certain thread between the yolk sac and the result of gestation.

In addition to studies using ultrasound equipment, biochemical screening is done in the period from 10 to 12 weeks. Blood sampling must be taken on the same day on which the ultrasound was performed. The analysis will reveal the likelihood of having a child with chromosomal abnormalities.

What is a yolk sac?

The yolk sac or gestational sac is a circular sac attached to the abdominal cavity of the embryo. Inside the sac is the vital yolk, which plays a vital role in the development of the fertilized egg during placentation.

This organ is present in many mammals, birds, fish and cephalopods in the early stages of development and remains throughout life in the form of a cyst-shaped process in the intestine with remaining yolk.

Main functions of the yolk sac

Without this small bubble, the full development of the fertilized egg is impossible. It takes on many functions, including nutrition and respiration of the embryo, while the appropriate organs for this are absent.

In addition to nutrition and respiration, the membrane membrane with the yolk serves as the primary circulatory system, through which oxygen and nutrients are transferred to the embryo.

Yolk sac during pregnancy

The gestational sac is evidence of a healthy intrauterine pregnancy. During ectopic gestation, this membranous membrane is not visualized. The “bag” appears in the second week of embryonic development and protects the fetus almost until the end of the first trimester, until other organs begin their work.

Between the fifth and sixth weeks, the sac should be clearly visible on ultrasound. This is one of the important criteria for the proper development of the embryo. The average diameter of the membrane shell is 5 mm.

Between the seventh and tenth weeks, the size of the bubble normally reaches up to 6 mm in diameter.

After 10 weeks, the yolk sac gradually ends its activity and must necessarily decrease in size. By the beginning of the second trimester, the fully formed placenta takes over the function of nutrition and breathing, and the yolk membrane is absorbed into the fetal cavity and in its place only a small appendage remains in the umbilical cord area.

Yolk sac norms by week

The gestational sac appears in the second week after conception; it is visible on the ultrasound monitor only in the fifth and sixth weeks. During the research, doctors determined the norms for the diameter of the yolk sac based on the timing of embryo development. These norms are considered signs of a favorable pregnancy:

1. In the fifth week – 3 mm.
2. At the sixth week – 3 mm.
3. In the seventh week – 4 mm.
4. At the eighth week - 4.5 mm.
5. At the ninth week – 5 mm.
6. At the tenth week - 5.1 mm.
7. At the eleventh week - 5.5 mm.
8. At the twelfth week - 6 mm.
9. At the thirteenth week - 5.8 mm.

After 10-12 weeks, the gestational sac begins to decrease in size.

What does not visualizing the yolk sac indicate?

Modern equipment makes it possible to detect and reduce the risk of complications during pregnancy at any stage. If, during the examination, the yolk “vesicle” is not visualized during the period between six and ten weeks, this indicates an unfavorable course of pregnancy. Because this organ can accurately assess the state of development of the embryo.

The absence of a gestational sac is a sign of a missed or undeveloped pregnancy. In case of a frozen pregnancy, urgent cleaning of the uterine cavity is necessary, but it is necessary to first conduct repeated studies after 7 days to ensure the accuracy of the diagnosis.

An undeveloped gestational sac in the fertilized egg often indicates a lack of the hormone progesterone. Timely treatment with drugs containing progesterone allows you to save the fetus and avoid subsequent complications.

What do increases and decreases mean?

Small deviations from the norm in the size of the yolk sac are not an indicator of any pathology or threat to the fetus.

A belated decrease towards the end of the first trimester indicates the slow resorption of an already unnecessary organ. Additional examination is necessary after 7 days to ensure that there are no abnormalities in fetal development. If there are no pathologies and all other indicators are normal, then there is no reason to worry either. If any abnormalities are detected, cleaning the uterine cavity is recommended. The shorter the period, the safer it is for the mother’s health.

An increase in the size of the yolk sac above normal also does not immediately indicate an existing pathology. Diagnostics are required to determine possible causes. Taking certain medications, poor diet and stress can cause an increase in the diameter of the yolk sac. Or simply an individual feature that does not portend any threat to the fetus. The doctor must perform a repeat ultrasound to clarify and confirm the diagnosis.

An increase, decrease, irregular shape or compaction of the shell with nutritious yolk from the established standards is significant only in conjunction with violations of other indicators.

Is your yolk sac the right size for your due date?

YesNo

Many expectant mothers, when entering an ultrasound room, hear about the yolk sac during pregnancy. However, the ultrasound doctor does not always give complete answers to all the questions of pregnant women.

What is the yolk sac during pregnancy - not to be confused with the corpus luteum

Even before conception, an egg is formed in one of a woman’s ovaries; when it unites with a sperm, it will give a new life - the life of your child. In the middle of the menstrual cycle, the "sac" or dominant follicle containing the mature egg, lop

is released, and the egg is sent to the uterus through the fallopian tubes. And in place of the burst sac, the formation of a corpus luteum occurs, the purpose of which is the production of progesterone. This hormone is extremely important; it is designed to support and preserve future pregnancy in the first trimester. Hormones produced by the yolk sac help prevent rejection of the fetus after attachment - implantation (i.e., reduce the risk of miscarriage, spontaneous abortion), prepare the mammary glands for lactation, lower blood pressure and suppress the immune system, which ensures a loyal attitude of the mother's body to the new , actively developing life.

Yolk sac, what is it?

After conception, on days 15-16 of pregnancy, the yolk sac is formed. Being a “temporary organ” of the baby, the yolk sac during pregnancy is an appendage located on the ventral side of the embryo. It contains a supply of yolk necessary for development. At first (before the start of the functioning of the fetus’s own organs), it performs the functions of the liver, spleen, and is also a supplier of primary germ cells, actively participating

plays a role in the formation of immunity and metabolic processes.

The meaning of the yolk sac size

According to studies, an increase or, conversely, a decrease in the yolk sac, as well as an irregular shape, are often accompanied by a frozen pregnancy. This is why it is so important to assess the size of the yolk sac during pregnancy.

Ultrasound of the first trimester

During ultrasound examination in early pregnancy, it is the yolk sac that is an important diagnostic criterion. This is due to the fact that the size of the yolk sac in the first nine weeks of pregnancy significantly exceeds the size of the child. During pregnancy, the yolk sac begins to be visualized at 5.5 weeks. In a normally developing pregnancy at 5-10 weeks, the size of the yolk sac should be less than 5.5 millimeters. From 8 to 12 weeks of pregnancy

The size of the yolk sac should be more than 2 millimeters.

Yolk sac reduction

At the beginning of the fourth month of pregnancy, the fetus is already fully formed, and placental blood circulation begins, as a result of which the yolk sac, which has become unnecessary during pregnancy, disappears in later stages. However, there are cases when its reduction (disintegration) is delayed, and its cystic degeneration occurs. This fact should not cause much concern, provided that all other indicators of the screening ultrasound were normal. If concern persists, you can do an ultrasound again - in about 2-3 weeks.

What is SVD during pregnancy and how to determine it on ultrasound? There is only one answer to this question.

SVD is the average internal diameter of the ovum according to ultrasound diagnostics. This indicator is measured exclusively in millimeters.

Fertilized egg illustration

The gestation period is characterized by certain values ​​of the internal diameter. The digital value of the SVD constantly varies, so the period is calculated with an error of a week to a week and a half. A more reliable sign for clarifying the gestational age using ultrasound is the CTR (coccygeal-parietal size) indicators. It should be noted that the coccygeal-parietal size of the embryo is less subject to individual fluctuations compared to the average internal diameter of the ovum, and therefore is used more often to establish a reliable gestation period. The error is approximately three days.

When the fetus is well visualized, the period is determined by the length of the fetus, and not by the internal diameter. The coccygeal-parietal size is recorded during a routine ultrasound and reflects the actual size of the fetus in combination with the approximate weight of the fetus. As a rule, measurement of CTE indicators is used up to 12 weeks of gestation, and in later ultrasound studies, the biparietal diameter of the circumference of the head and abdomen of the fetus is used.

Approximate indicators of SVD, depending on the timing of gestation

• When the diameter of the ovum is approximately 4 millimeters, the gestation period is no more than 5 weeks. It is possible to assume that about four weeks have passed since conception.
• Closer to the fifth week, the diameter will reach 6 millimeters.
• After a few days, the fetus becomes 7 millimeters.
• By the end of the 6th week, the diameter increases to 12 - 18 millimeters.
• The average value of SVD at a period of six weeks and five days is 16 millimeters.

Fertilized egg on ultrasound

Of course, the expectant mother is concerned about the following question: how intensively does the fetus grow in the second and third trimester? We can say with confidence that until 15 - 16 weeks, its diameter grows by one millimeter every day. Then its value increases by an average of 2 - 2.5 millimeters every day. During the border period of 16 - 17 weeks, they stop measuring the internal diameter of the fetal egg, focusing on more reliable indicators.

Ultrasound examination at short gestation

Diagnostics are carried out for the following purposes:

Diagnosis of the localization of the fertilized egg

1. Establishing the exact location of the fetus (in the uterine cavity or outside it). When the fetus is located outside the uterus, we are talking about ectopic pregnancy. When the fetus cannot be visualized or the recognition process becomes significantly more difficult, they resort to precise determination of the embryo’s heartbeat. Signs of fetal viability may be found in the fallopian tubes or abdominal cavity.

In addition to this complication, other complications may appear in the initial stages of pregnancy: for example, a changed shape of the fertilized egg; improper attachment; high risk of placental abruption and other pathological disorders.

2. Determining a single or multiple pregnancy is not difficult. In the uterine cavity there are two or more fetuses with active life activity.

3. Assessing the main dimensions of the fertilized egg and embryo and comparing them with normal values.

4. Study of the correct structure of the embryo and fertilized egg to exclude serious congenital developmental anomalies. These may be chromosomal mutations (for example, Down syndrome).

5. Vital signs are assessed based on the presence of a heartbeat, which is detected already in the fifth week of gestation. The motor activity of the embryo is quite well determined after the seventh week of gestation.

At the initial stage, the movements are so weak and isolated that they can hardly be distinguished during an ultrasound. As the embryo grows, motor activity begins to resemble characteristic flexion and extension movements, and then active movements of the upper and lower extremities. Since individual moments of motor activity are quite short in time and are calculated in seconds or their fractions, the definition of cardiac activity is used to register the fact of fetal life.

6. Detection of a corpus luteum in one of the ovaries. This small cystic formation provides the expectant mother’s body with important hormones to preserve the fetus in the early stages of development.

7. The study of amnion and chorion comes down to their ratio depending on the period of gestation already in the first trimester. Based on the obtained ultrasound results, it is possible to predict the further course and outcome of pregnancy.

Ultrasound is indispensable for determining possible problems with pregnancy

8. Diagnosis of a threatened miscarriage using ultrasound allows one to recognize early symptoms, which are characterized by a clear thickening of one of the walls of the uterine cavity, as well as a significant increase in the internal os. In case of a possible miscarriage, ultrasound assesses the vital signs of the fetus and the condition of the uterus and placenta as a whole.

9. Diagnosis of diseases and possible malformations of the female genital area (anomalies of the vagina or uterus). Any deviation from the norm determines the course and outcome of pregnancy.

Typical signs and features of fertilized egg implantation

Often, the fertilized egg attaches to the wall of the uterus several days after unprotected sexual intercourse, and then the egg is implanted into the endometrial layer after fertilization. From this moment on, the woman’s body begins to actively produce the hormone hCG (human chorionic gonadotropin), to which the pregnancy test strip reacts.

Implantation of fertilized egg

The screening test will not always be positive, so it is necessary to resort to a reliable blood test to determine hCG. After receiving a positive test result, you must immediately contact a gynecologist at the antenatal clinic for registration and further observation for nine months.

A formed fertilized egg is the surest sign of pregnancy. It has a characteristic oval shape and is quite well visualized on ultrasound in the third week of absence of menstruation.

The embryo itself can only be seen when the period reaches the fifth week. If the ultrasound doctor does not detect an embryo in the fertilized egg, then the study is repeated after about half a month. As a rule, the embryo becomes more clearly visible, and its heartbeat is also detected. In other cases, we are talking about pathological development or even a frozen and undeveloped pregnancy.

That is why it is very important to undergo an ultrasound to exclude possible complications for further correction of the situation. The first trimester is the most important period of gestation, since throughout its entire duration all the organs and systems of the unborn baby are actively formed.

Timing of routine ultrasound diagnostics

Based on the results of the WHO, strict periods have been defined for conducting mandatory ultrasound examinations during the gestation period of the unborn baby.

Three ultrasound screenings are required

At other time intervals, the examination is prescribed strictly according to individual indications from the mother and fetus:

• The first ultrasound examination is recommended to be carried out at 12 - 14 weeks;
• the second screening is prescribed at 20 - 24 weeks;
• The third ultrasound visit is necessary at 32 - 34 weeks of gestation.

It is not advisable to neglect the timing of the next examination, since it is during the specified period of gestation that it is possible to recognize fetal malformations. And if a forced need arises, an interruption for medical reasons. The last screening examination can also be carried out at a later time.

The results of the current diagnostics may be significantly outside the normal range, but this is far from a cause for concern. Do not forget that the development of each child has its own characteristics. However, you should not ignore the identified symptoms either.