In the absence of menstruation, every woman thinks about the reasons. The most accessible and reliable method is ultrasound, which is successfully used to determine pregnancy in a short time.

After fertilization, the resulting zygote goes through the fallopian tube into the uterine cavity, gradually increasing in size on its way. Starting from the 22nd day, its diameter is 3–5 mm. This is enough so that on the 5th day after the delay of menstruation, an ultrasound scan can be done to determine the presence of an embryo.

Not always ovulation occurs strictly in the middle of the cycle, it can occur 7-10 days earlier or later. Ultrasound with a delay should be carried out no earlier than after 5 days of the absence of menstruation. This is the minimum period that allows you to definitely establish the presence of an embryo in the uterus, as well as to determine which week of gestation the expectant mother is.

If the cycle period is constant, then this helps to more accurately and quickly determine the time of gestation than with a floating menstruation schedule. For the baby, there will not be much difference in how many days after birth it will be found on an ultrasound scan, therefore it is better for women with an irregular cycle to come for an examination with a delay of 1 week or more.

An examination is necessary not only to find out the gestational age of the expectant mother, but also an ultrasound shows where the embryo is located and how it attached. This is important for the further management of the pregnant woman.

Indications and contraindications for examination

There are 2 types of ultrasound that are done to determine pregnancy - transvaginal and abdominal. It is advisable to go for an examination no earlier than 5 days after the delay.

1. Vaginal examination is more specific for the first month of pregnancy. With its help, the embryo will be visible already 21 days after conception.
2. An abdominal ultrasound is unable to detect pregnancy at 3 to 4 weeks due to being conducted through the abdominal wall. Therefore, it can show conception later than transvaginal, with a difference of 2 weeks.

Ultrasound is indicated in the following cases:

1. Absence of menstruation on the expected date.
2. Pulling sensations in the lower abdomen.
3. Pain in the abdomen, especially in the lower part of it.
4. Delay in the presence of an intrauterine device.
5. The presence of chronic gynecological diseases.
6. Bleeding that does not coincide with the cycle.

The examination helps to identify the source of complaints, since not only during pregnancy, critical days are late.

There are no contraindications for ultrasound. The only factor that can be taken into account here is the woman's personal unwillingness to be examined.

The choice of a method for determining pregnancy after a conception that has taken place, which can show it at the earliest possible time, remains with the doctor, but preference is given to the transvaginal ultrasound method.

For the most reliable confirmation of fertilization, determining the gestational age, examining and evaluating the embryo, it is better to do an ultrasound transvaginally.

The fact of determining the timing of pregnancy as accurately as possible, as well as examining the fetus, is important, because in the period up to 12 weeks it is possible to have an abortion for medical reasons if malformations that are incompatible with life are found.

For more information about ultrasound diagnostics during pregnancy, see the story:

How to prepare for an examination

According to the standards of the survey, the primary ultrasound examination, it is used to determine pregnancy and to identify other likely culprits for the absence of menstruation, namely:

• endometrial polyps.
• Uterine fibroids.
• Endometriosis.
• Ovarian cysts.

Carrying out any ultrasound study is hindered by increased gas formation, which makes it difficult to visualize. To reduce the formation of gases 2-3 days before the examination, you need to reduce the following foods in the diet:

• Legumes.
• Fresh black bread.
• cabbage.
• Whole milk.
• Fatty meats.
• Baking.
• Carbonated drinks.

For abdominal ultrasound, it is desirable to fill the bladder. To do this, 1–2 hours before the examination, you need to drink 500–1000 ml of liquid, preferably clean drinking water. Before a transvaginal ultrasound, the bladder must be emptied after visiting the ladies' room.

How is an ultrasound done to determine pregnancy

If menstruation does not occur, 2 types of ultrasound are done to determine a probable pregnancy. Transabdominal, in which the doctor guides the sensor along the belly of the expectant mother, and transvaginal, that is, by inserting the sensor into the vagina.

To determine pregnancy with a delay of up to 1 week, the most accurate is transvaginal ultrasound. With abdominal ultrasound, the signal to the embryo needs to travel a greater distance, therefore, with gestation up to 5 weeks, nothing can be seen.

Description of the two methods:

• Transvaginally. The examined pregnant woman lies on the couch on her back, bends her legs at the knees and slightly spreads to the sides. The doctor performs an ultrasound using a special vaginal probe, which has a peculiar shape and a certain diameter to facilitate its insertion. This prevents the possibility of feeling pain during the examination. A condom is first put on the sensor.

• Transabdominally. The woman is located on the couch on her back, her legs lie horizontally, less often - bent at the knees. The doctor conducts an examination using a conventional surface sensor, which he leads along the stomach. In the presence of a pronounced layer of subcutaneous fat, a study to determine pregnancy may be inconclusive.

Deciphering the results

Up to 12 weeks of pregnancy, the unborn baby is called an embryo or fetus. It will later be called fruit. On the very first ultrasound, the embryo looks like a hyperechoic (dark), i.e., not a hollow formation inside. It is located at the exit of the fallopian tube or attached to one of the walls of the uterus. This is called a fertilized egg.

Distinctive features of the embryo - it has a yolk sac, a thin shell. This helps to differentiate early pregnancy from a polyp, cyst and other formations. To determine the gestational age, there are special tables.

Ultrasound is also done to determine the location of the embryo. If it is outside the uterus, then this is an indication for emergency surgery. If there are signs of increased uterine muscle tone, the question is raised about the threat of abortion and treatment.

See what a fetal egg looks like on an ultrasound monitor:

Are diagnostic errors possible?

During the ultrasound, as with any study, there may be inaccuracies or errors in obtaining the result. The main reasons why doctors could not see pregnancy on ultrasound:

1. Early treatment - the period is too short to visualize the ovum.
2. late ovulation.
3. Inflammatory process in the uterus, hiding a small embryo.
4. Outdated equipment.
5. Human factor.

A doctor can make a mistake and assume pregnancy on ultrasound with the following diseases and conditions:

• polyp;
• myoma;
• hematoma.

The accuracy of obtaining a reliable result depends not only on the specialist in ultrasound diagnostics, but also on the pregnant woman. The error in calculating the menstrual cycle, the incorrectly named date of the last menstruation, the unwillingness to talk about the presence of gynecological diseases makes it difficult to diagnose.

You can determine pregnancy literally from its first days, even before the delay in menstruation, by donating blood to the level of hCG, the pregnancy hormone. Its level will increase in direct proportion to the growth of the embryo.

How much does research cost

Ultrasound to determine pregnancy is carried out free of charge under the CHI system when contacting a antenatal clinic. If desired, or in the absence of SNILS, an insurance policy, you can contact a private clinic. The average cost of the examination is 1.5-2 thousand rubles.

The use of ultrasound is the most affordable and safest means for determining pregnancy, including at short terms. However, you need to remember about the timeliness of contacting a gynecologist, the optimal period for this is from the 5th to the 12th obstetric week. It is at this time that it is possible to assess the embryo, its condition and identify gross malformations.

When did you arrive for your first ultrasound? Tell us in the comments about your experience of determining pregnancy. If you liked the article, then share it with your friends.

The pioneer in the field of gynecological ultrasound diagnostics was the Austrian doctor A. Kratochwil. In the early 60s, A. Kratochwil presented his study of the fetal heart rate at the 6th week of gestation using a transvaginal sensor. Over the past decades, ultrasound in medicine has undergone amazing changes and has revolutionized obstetric diagnosis and pregnancy monitoring.

Why do an ultrasound in the early stages

During the first trimester of pregnancy, a unique and dramatic sequence of events occurs that defines the most critical and sensitive period of development: the remarkable transformation of a single cell into a fully recognizable person. Due to the complex sequence of events that accompany the development of the embryo in the first trimester, complications often arise. Approximately 15% of clinically diagnosed pregnancies are spontaneously terminated. The loss rate is estimated to be two to three times higher in very early pregnancy, in so-called biochemical pregnancies.

Currently, ultrasound is the main available method for differentiating between normal and abnormal early pregnancies. With the help of ultrasound up to 11 weeks, complications such as:

blistering,

anembryony,

undeveloped pregnancy,

incomplete and complete spontaneous miscarriages,

retrochorial hematomas,

ectopic pregnancy.

Is it possible to find out by ultrasound when pregnancy occurred

A common use of ultrasound in early pregnancy is to calculate gestational age (obstetrical gestational age). For this purpose, ultrasound is considered a very precise method. It is not uncommon for a woman to have irregular periods, ovulate late or early, or not remember the first day of her last period at all. In these cases, ultrasound comes to the rescue. In a normal pregnancy, ultrasound results can give an estimate of gestational age with an accuracy of 5-7 days and answer one of the most exciting questions of many pregnant women -.

When a woman has symptoms of a miscarriage, the doctor may order one or more ultrasounds to determine the viability of the embryo. Spotting spotting often accompanies an ectopic pregnancy and ultrasound is the only non-invasive method for diagnosing this complication before the development of a fallopian tube rupture clinic.

Which ultrasound is better for determining pregnancy and how is ultrasound done in the early stages

The study can be performed transvaginally (with a vaginal probe) or transabdominally (through the abdomen). During the first trimester, doctors usually use a transvaginal ultrasound rather than an abdominal ultrasound to obtain information about the pregnancy. Transvaginal ultrasound provides the most accurate information in the early stages of pregnancy due to the fact that by this time the fetal egg and fetal pole are still extremely small, and the vaginal probe allows you to get as close as possible to a developing pregnancy. In a transvaginal ultrasound, the doctor inserts a special thin probe into the vagina to take a series of measurements, including the size of the gestational sac, the size of the yolk sac, the coccygeal-parietal size (CTE), and the presence of a heartbeat.

On a transabdominal ultrasound, a woman will be asked to come in for a scan with a full bladder because this positions the uterus in a way that makes it easier to take measurements. The doctor then applies the gel to the lower abdomen and uses a transducer to measure from different angles.

When can I do and expected results of ultrasound in early pregnancy

These data in most cases are detected by transvaginal ultrasound. As a rule, transabdominal ultrasound is less sensitive at such early stages of pregnancy.

Thus, to rule out an ectopic pregnancy, you may be advised to have your first ultrasound as early as 5 weeks (approximately a week of delayed menstruation). At this time, the fetal egg is already visualized in the uterine cavity, and at the same time it is not yet large enough to cause a rupture of the fallopian tube in case of tubal pregnancy.

If the first early ultrasound is done to make sure that the pregnancy is developing, then it is better to wait at least 6-7 obstetric weeks of pregnancy. Ultrasound at an early stage will also help answer such an important question as whether this pregnancy is singleton or multiple, as well as to distinguish between monochorionic and dichorial pregnancies.

Another important point when it is recommended to conduct the first or repeated ultrasound in the first trimester of pregnancy is the obstetric period of 8-9 weeks. The fact is that most stops in the development of pregnancy occur in the period before this period. A normally developing pregnancy at 8-9 weeks is clearly visible with a transabdominal sensor. At this time, the embryo begins to make the first movements and can already wave its arm or leg. If everything is normal at this stage, then the next ultrasound is recommended as early as 12-13 weeks in order to screen the first trimester of pregnancy.

Why the results of a single ultrasound in the early stages may not be sufficient for an accurate diagnosis and will ultrasound always show early pregnancy

The results of the ultrasound are compared with what is expected to be seen at a given gestational age. Gestational age is calculated from the number of weeks since the last period, however this method usually assumes a 28-day cycle with ovulation occurring on the 14th day. Many women have shorter or longer cycles and ovulate later or earlier. As a result, your baby may be younger or older than expected and this may affect what the ultrasound shows. For example, if a woman has a 35-day menstrual cycle, she is likely to ovulate around the 21st day of her menstrual cycle (ovulation usually occurs two weeks before her period starts). If such a woman became pregnant and did an ultrasound six weeks after the date of her last menstruation, then the ultrasound will show a picture characteristic of 5 obstetric weeks. Despite the fact that this is a normal pregnancy, the gestational sac will be small for 6 obstetric weeks, it is possible that even the embryo and yolk sac will not be visible. A woman and an ultrasound doctor often do not know when exactly she ovulated, and the data obtained can cause unnecessary concern about a non-developing pregnancy. It can be even more difficult to figure out when ovulation occurred two weeks later. The fetal egg may not be visualized in the uterine cavity and it becomes necessary to carry out a differential diagnosis with an ectopic or biochemical pregnancy.

Also, often a woman does not remember exactly when she last had her period and calls the date “at random”. By specifying the wrong day, even with a typical 28-day cycle, during an ultrasound, you can see something completely different from what was expected.

Remember that any uncertainty about the exact date of ovulation can affect what the ultrasound shows up to 11 weeks of pregnancy.

In this regard, sometimes the doctor cannot accurately determine the result based on only one early pregnancy ultrasound and recommends a follow-up ultrasound after 7-10 days. Waiting for a follow-up ultrasound can be emotionally very difficult, but it may be necessary to avoid misdiagnosis, especially if there is no other information to help the doctor interpret the ultrasound results. In most cases, such an assistant is a blood test for hCG, but its data must also be interpreted in dynamics.

The American Pregnancy Association Guide ( The American Pregnancy Association it is stated that if the average internal diameter of the fetal egg is more than 16-18 mm and does not contain an embryo complex, or if the CTE of the embryo is more than 5 mm and it does not have a heartbeat, then such a pregnancy should be regarded as non-developing. In our country, more cautious recommendations have been adopted: the SVD of the fetal egg should be more than 25 mm and the CTE of the embryo should be more than 7 mm.

How hCG blood test results or other information can help interpret the ultrasound picture

In cases where there is any question as to whether a given pregnancy is progressing based on an ultrasound scan, the doctor will usually order a follow-up ultrasound after a few days. However, the presence of other diagnostic information may help the clinician interpret the ultrasound results, even if there is only one ultrasound. For example, a woman took a pregnancy test or donated blood for hCG on the day of her missed period and it was negative, and after another two weeks of delay, an ultrasound scan showed 4-5 weeks of pregnancy. So, with a high probability, pregnancy did not occur on the 14th day of the menstrual cycle, but 7-10 days later. And vice versa, if on the day of the delay of the monthly test was already positive, and two weeks later we see a picture characteristic of 5 weeks of pregnancy, there is a high probability of a non-developing pregnancy.

The data of a blood test for hCG are very important in cases where a fetal egg is not visible in the uterine cavity. At an hCG level of more than 1000 mIU / ml, the fetal egg should be determined in the uterine cavity. If this is not the case, then this situation requires the exclusion of an ectopic pregnancy. On the contrary, with low hCG numbers, despite the fact that there is a pregnancy, we do not expect to see its signs with the help of ultrasound.

With a normally developing pregnancy, the level of hCG increases according to certain laws:

Normal HCG doubling time

HCG level Doubling time
1200 mIU/ml 48-72 hours
1200 - 6000 mIU / ml 72-96 hours
More than 6000 mIU/ml More than 96 hours

Since the level of hCG has a large variability, it is not used to determine the exact gestational age.

The information in this step-by-step guide applies to ultrasounds performed in early pregnancy, especially early in the first trimester, during the first seven weeks of pregnancy. As pregnancy progresses, ultrasound becomes an increasingly accurate and informative method for assessing the condition and intrauterine development of your baby.

We monitor the development of the baby by weeks

The ultrasound procedure is mandatory during pregnancy, since with its help the doctor receives information about the condition of the fetus, which is of great importance. To date, scientists have proven that Ultrasound during pregnancy is absolutely safe, and ultrasound does not adversely affect either the woman or her child.

Diagnostic methods

For ultrasound, the doctor uses a special transducer, from which ultrasonic waves are elusive to human hearing. They are able to penetrate into the human body, allowing the specialist to see the state of the internal organs of not only the woman herself, but also the child. The principle of their operation is simple: when the ultrasonic waves transmitted by the transducer reach any organ, they are reflected and returned back, sending information to the device. It is her, but in an already processed form, that can be observed on the screen of the device.

There are several ways to conduct an ultrasound during pregnancy:

• transvaginal way. It is carried out with the introduction of the sensor into the vagina. It is most often used in early pregnancy, because it allows you to most clearly observe a still very small fetus.
• screening method. It is performed through the skin of the abdominal wall, on which a layer of a special gel is applied before the procedure. This is done so that ultrasonic waves penetrate better into the abdominal region. If this type of ultrasound is prescribed at an early stage of pregnancy, then a woman is recommended to drink 0.5 liters of water 1.5-2 hours before the procedure to fill the bladder. In the future, when the embryo becomes larger in size, such a need disappears.

Types of ultrasound

Types of ultrasound

• Ultrasonic fetometry. This procedure allows you to accurately determine the duration of pregnancy, as well as to identify violations in the development of the fetus. The main parameters that are used for this analysis are biparental and coccyx-parietal size, abdominal and chest circumference, etc. These data are entered into a special table, with the help of which the gestational age is calculated.
• Doppler. It is customary to consider this method of ultrasound examination as additional, since it can only be prescribed by the attending physician. Doppler is used to assess the nature and speed of blood flow in the vessels.
• Screening ultrasound. This is a standard type of ultrasound examination. It is prescribed several times during the entire period of pregnancy to monitor the development of the fetus.
• 3D ultrasound. This is a relatively new type of ultrasound, which is prescribed from 24 weeks. The 3D image helps the clinician avoid some of the mistakes that can be made by looking only at the 2D image.
• 4D ultrasound. This type of ultrasound is now very popular, since the four-dimensional image allows you to examine the baby in more detail, both to his parents and doctors.

Timing and frequency of the procedure

Ultrasound examination is performed at various stages of pregnancy. There are several periods of time when a pregnant woman is scheduled for a routine examination:

• 5-8 weeks. Ultrasound is prescribed primarily to confirm the fact of pregnancy, as well as to determine the place of attachment of the fetal egg. The conclusion about the viability of the embryo is established by the presence of heart contractions and motor activity.
• 10-12 weeks. In this case, diagnosis is required to clarify the duration of pregnancy and to confirm its progressive condition. The size of the collar zone is measured, namely the thickness of the soft tissues in the neck, to exclude the possibility of chromosomal diseases. Ultrasound at this stage of pregnancy allows you to determine the place of attachment of the placenta, the quality and quantity of water. If any complications are detected, such as uterine hypertonicity, isthmic-cervical insufficiency, etc. After some time, the woman is assigned an additional examination. During this period of time, the doctor can determine the expected date of birth with a minimum error.
• 22-24 weeks. This period of pregnancy is considered very important, because it is during this period that ultrasound diagnostics can detect or exclude malformations of the embryo, determine whether the size of the fetus corresponds to the established gestational age. Also, with the help of ultrasound, the doctor examines the condition of the placenta and water.
• 30-32 weeks. During this period, the sensor evaluates motor activity. Most often, an additional Doppler study is carried out, which allows you to find out whether the child receives enough nutrients from the mother through the placenta or not. In addition, the Doppler study allows you to predict how the birth will go.
• Ultrasound diagnostics before childbirth. Allows you to see the position and condition of the child, as well as determine its weight.