CTE of the fetus 4 mm what is the gestational age. Why is the CTE of the fetus determined by week

CTE (coccygeal-parietal size) can be determined with a sagittal scan by measuring the distance from the crown of the fetus to the coccyx. This technique allows you to find out the age of the embryo and its size with maximum accuracy. Based on this data, the physician can judge the growth and formation of the fetus, and also help to avoid any abnormalities.

CTE of an embryo in the early stages

In order for the CTE results to be as accurate as possible, a picture of the fetus must be taken at a time when it is in a more unbent state... The distance is measured from the highest point of the crown to the coccyx. It is believed that CTE is the most accurate indicator that determines the duration of pregnancy, since it does not depend on the race, individual characteristics and gender of the child.

If the coccygeal-parietal size does not correspond a little to the required norm, there is no need to worry: These results are compared with the KTP table by weeks of pregnancy, and it is impossible to accurately predict the development of a child, relying only on these data. Each fetus has its own physiological characteristics. However, if the CTE increases over a period of several weeks, then there is a likelihood of having a baby weighing 4 or even 6 kg.

Despite the fact that the readings of the CTE of the fetus and the table do not always coincide, it is still worth taking into account its values. The reasons for a large CTE can be:

• the mother has diabetes mellitus;
• obesity in a pregnant woman;
• the use of drugs that promote metabolism;
• taking various vitamin complexes.

The larger size of the embryo is also a signal that the expectant mother should limit herself from excessive consumption of foods that increase cholesterol. A more severe case is the occurrence of neoplasms, that is, the presence of congenital defects.

Consequences of abnormal fetal development

In most cases, a group of drugs provokes fetal growth, and up to critical parameters. While still in the womb, the baby can weigh more than 5 kg. Taking into account the data of the KTP table by week, doctors at an early stage of pregnancy can adjust the size of the fetus.

If the CTE is much lower than the tabular value, then in most cases the cause may be a later date of fertilization of the egg. In order to confirm the absence of any pathologies, doctors prescribe an ultrasound scan.

Otherwise, the woman's body, and the unborn child itself, may suffer greatly. Having established the cause and form of the deviation, specialists can provide timely assistance and correct the development of the embryo.

In the womb, the baby grows and increases in size: every day by 1 or 2 mm. And this will help to make predictions of the readings of the KTP table of the fetus by week and day, by determining the deviation rate, which should not exceed 3 days. Therefore, from the 7th week of pregnancy to the 15th week, the table is the main indicator of the child's growth. At the 16th week, the life and development of the fetus is monitored by doctors using ultrasound.

At the 7th week of pregnancy, the maximum size from the head to the coccyx should not exceed 11 mm, and the average value at the 8th week is 14 mm. At the 11th week, the average CTE value is ideally 41 mm, and at the 13th week, approximately 54-56 mm, no more than 71 mm. The maximum value (95 percentile) at 14 weeks gestation should not exceed 86 mm.

Since the CTE value is measured in millimeters, in order to calculate it yourself, a calculator is not needed. In the womb, the child should grow and develop in moderation., in accordance with established standards.

The coccyx-parietal size (CTE) is the greatest distance from the coccyx to the central point of the head (crown) of the fetus. This indicator allows you to very accurately, with an error of 1 to 4 days, determine the duration of pregnancy and the date of delivery. With an irregular cycle, this method will be more correct than determining the timing of pregnancy by ovulation, and with regular menstruation, they usually simply compare the values ​​obtained with the obstetric period.

The shorter the gestation period, the more informative this indicator. The embryo still has practically no limbs, but only a heart and a little body. Therefore, the size of the fetus allows you to assess its condition and follow the development after some time.

Thanks to the measurement and tracking of sizes over several weeks (dynamic research), it is possible to identify abnormalities in the development of the baby in the early stages. Doctors monitor the CTE from 7 to 11 (less often 14) weeks of pregnancy, after which they already use other values ​​for monitoring the baby - fetometry. The ideal time to measure CTE is 11 weeks. At this time, they usually appoint.

How is the size of the fetus measured?

To determine the coccygeal-parietal size, ultrasound is used. The doctor scans the fetus, conventionally dividing the body into two symmetrical halves, and measures the length of the fetus from the crown to the coccyx several times. After that, it chooses the maximum of the received sizes. If the baby moves during scanning, the CTE is measured at the moment of its greatest extension.

Preparing for the study is simple - you need to do it on an empty stomach and drink 1 liter of water an hour before the ultrasound scan.

The obtained values ​​are compared with the tabular values ​​of the CTE of the fetus by weeks of pregnancy.

With the course of pregnancy, the size of the fetus is constantly increasing, which allows us to conclude to some extent that the pregnancy is proceeding normally and the baby is also in order. The table shows the normal CTE values: minimum (column 5-percentile), average (column 50-percentile) and maximum (95-percentile).

If a more accurate measurement is needed, tracking the size of the fetus in dynamics, tables are used by weeks and days of pregnancy.

It should be noted that all decoding of the results must be carried out with a doctor. This will save you from wrong conclusions and unnecessary worries. Minor deviations from the norm may not mean that the child has anomalies. Since the fetus is increasing in growth every day, the tables are developed for each day of pregnancy from 7 to 14 weeks. But at the same time, a deviation in the size of the baby is allowed, corresponding to 4 days. In the second trimester, the measured CTE often does not correspond to the average statistical value. From 16 weeks, the coccygeal-parietal size of the fetus is not taken into account in examinations.

Fetal development at 11-12 weeks of gestation

The first routine ultrasound examination is usually scheduled at 11-13 weeks. The first trimester is already behind and a new stage in the development of the baby begins. At this time, the hormonal system begins to work actively in the fetus and the work of the brain improves. The internal organs are also preparing with might and main - the intestines begin to contract, and the kidneys are filled with urine. The structure of the skeleton changes - cartilage replaces bone tissue. At 12 weeks, the membranes on the fingers disappear in the embryo, and after a week it first tries to move and bend the hands. At the end of the twelfth week of pregnancy, the average size of the fetus is 5.3 mm. Further, the growth rate of the baby will increase - in a couple of weeks it will grow by 2 mm instead of 1 mm daily.

The opinion of some gynecologists on the advisability of conducting the first ultrasound study at 11 weeks is gaining popularity. It is during this period that some severe malformations of the embryo are best diagnosed. Also, at 11 weeks, you can most accurately determine the time of conception and, accordingly, calculate the expected date of birth. Usually, the gynecologist maintains both terms - obstetric, calculated from the last menstruation and the period that was established according to the CTE.

CTE more or less than normal

An increase in the size of the fetus indicates the dynamic development of the baby in the womb. But it happens that the CTE of the fetus increases rapidly and is increased by 1 week or more. This is not a reason to panic - you may just have a big baby. In this case, of course, it is worth paying attention to this and discussing the results of the study with the attending physician. You do not need to be treated with drugs that stimulate an accelerated metabolism. These include multivitamins and, for example, Actovegin. Perhaps the doctor will also revise your diet and ask you to give up too high-calorie and not very useful products... It is also necessary to exclude anatomical defects and diabetes mellitus in the fetus. All of these manifestations can affect the size of the baby.

It happens that the size of the fetus decreases at 11-13 weeks. At the same time, the tabular norms of the CTE of the fetus by week are not met. There may be several reasons:

Incorrectly determined obstetric gestational age... You may have ovulated well past the middle of your cycle. In this case, the CTE at 11-13 weeks will differ from the estimated obstetric period. In such cases, a re-examination is prescribed after 7-10 days. Based on the results of two measurements, a conclusion is made about the true gestational age.

Lack of hormones... Most often this is a lack of progesterone, which plays a very important role throughout the 40 weeks of pregnancy, and especially in. The danger of this kind of insufficiency is in the possible termination of pregnancy. The doctor usually prescribes appropriate medications that contain progesterone (, etc.)

, fetal death... If physical activity and cardiac activity are not observed, this is a signal for an urgent visit to your gynecologist. Timely consultation and medical intervention can save the life or reproductive function of a pregnant woman.

Infectious diseases... They also affect the development and size of the baby. They are identified with the help of special analyzes, after which directed therapy is carried out.

Diseases of the internal organs of the mother... These include heart and thyroid disease.

Disorders of the uterine mucosa... In this case, the fetus is unable to attach to the wall of the uterus and develop normally. This is often followed by spontaneous abortion.

Genetic disorders of the fetus... To determine this kind of diseases in the first trimester, along with ultrasound, a biochemical So, the CTE of the fetus is an indirect, but very important indicator of the development of the baby in the first trimester. Timely scheduled examinations and consultations with a gynecologist will help fill the pregnancy with pleasant expectations and hassles and minimize anxiety.

Determination of such a parameter as the CTE of the fetus by week, allows you to establish the correspondence of the size of the child in the womb with statistically averaged parameters, on the basis of which we can talk about his normal growth and formation. If there are deviations, doctors can detect them early, prescribe additional diagnostic tests and engage in corrective therapy so that a woman can give birth to a healthy baby.

After, held in the initial trimester of pregnancy, the expectant mother receives an image of her baby in her arms, indicating the main indicators of his development. Among them, the size of the coccygeal-parietal size is necessarily present, which is the most reliable diagnostic indicator of fetal formation. In addition, the CTE can be established, since normally this indicator is not very subject to fluctuations.

The coccygeal-parietal size, or abbreviated CTE, is an indicator of the size of the embryo, which is indicated in millimeters and is determined at various stages of pregnancy. Intrauterine measurement of the child is carried out at what is considered one of the safest ways to diagnose fetal development.

In the first trimester, the embryo has a curved shape, so you can measure the length of its body, taking into account the dimensions of the head and body. In this case, the determination is carried out between the points most distant from each other: from the crown of the head to the lower back. Therefore, the indicator is called the coccygeal-parietal.

Determination of CTE is carried out before 12-13 weeks of pregnancy, later diagnosis using this indicator is less informative, since starting with the doctor they look at other sizes and parameters of the fetus, which are united by one term "fetometry".

How is the indicator measured?

CTE depends on the duration of pregnancy, while the ratio of the two values ​​is in direct proportion, which means that the more time has passed since fertilization, the greater this indicator will be.

The size of the coccygeal-parietal size of the fetus is not affected by the following parameters:

• race;
• other individual characteristics.

If a woman has previously had, the exact duration of pregnancy can be determined based on the CTE data. With stable menstruation, the obtained parameters make it possible to confirm information about the time when conception occurred.

The coccygeal-parietal size is measured from week 6 to 14. Earlier determination is not possible due to the too small size of the embryo. Diagnostics for a period exceeding 15 weeks does not provide accurate information, in addition, other fetometric diagnostic tests can be carried out, on the basis of which the development and health of the baby is assessed.

The main criterion limiting the conduct of CTE is the education of a child's place (), which is why the indicator is recorded before a period of 13-14 weeks.

How is the CTE measurement carried out during ultrasound scanning of the fetus:

1. Diagnostics is carried out in a strictly sagittal projection, when the child's body is conditionally divided into two equal halves. In this case, the measuring line runs from the parietal region to the coccyx.
2. Indicators are established in the absence of fetal movement.
3. When the child is too mobile during the diagnosis, the doctor needs to wait for the moment when the baby's body is straightened as much as possible and fix the measurement.
4. The obtained data of the CTE of the fetus are verified with a statistical table, which indicates the values ​​of the indicator by weeks from conception.

Table by week

The table of values ​​allows you to compare the obtained survey results with the average indicators. But it is necessary to understand that the child grows daily and increases by 1-2 mm, so the comparison should be made strictly by day.

Deviations from the norm

A slight discrepancy between the indicators is considered normal, however, there are also more pronounced deviations from the tabular data, which may indicate the peculiarities of the child's development.

Exceeding the indicators for 1 week or more indicates that the fetus is. Therefore, a pregnant woman should limit herself to food, trying not to increase the average daily calorie intake, and also refuse to take metabolite drugs.

When the CTE data is much less than the average, there are several explanations for this:

1. Later than usual, therefore the pregnancy occurred later than it was determined at registration. For clarification, it is recommended to perform a subsequent ultrasound scan after 1-1.5 weeks.
2. when the embryo dies early. The criterion for confirming this fact is the absence. In such a situation, an emergency uterine cavity is required.
3. Hormonal imbalance resulting from insufficient production. After additional diagnostics, the patient is assigned or.
4. An infectious process, for the detection of which smears are taken from a woman for STIs, after which appropriate therapy is carried out.

If a genetic pathology is suspected, ultrasound screening should be performed, as well as additional diagnostics:

• amniocentesis - amniotic fluid is taken with a long thin needle for analysis;
• chorionic villus biopsy is a technique for detecting congenital pathology from biological material obtained from particles preceding the placenta.
• cordocentesis - obtaining blood from the umbilical vein, which is carried out through the abdominal wall of the mother.

The coccygeal-parietal size is the only reliable diagnostic indicator, on the basis of which in the first trimester of pregnancy it is possible to establish the exact period of conception, to monitor whether the fetus is developing normally, and if there are suspicions and deviations from the norm, to conduct an additional examination to determine the pathology and determine the method corrective therapy.

Useful video about ultrasound in the first trimester

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The future baby managed to successfully pass the embryonic segment of his life, and now he began to be called the fetus. Thanks to the application of the method for measuring the CTE of the fetus by week, the doctor can observe its development, detect the presence of pathologies in time or inform the young mother about the absence of any unwanted deviations in the development of the baby, as well as receive other information.

Let's take a look at what the term is. coccygeal-parietal size or KTP fetus... This size is the main and paramount in the process of determining the gestational age. However, it will completely depend on the same gestational age. The uniqueness of this method lies in the fact that the error in its determination can be at least 1 day, and maximum - 3.

Cases of menstrual irregularities in women are not uncommon. Then the obstetric term for determining pregnancy may be erroneous. Nevertheless, it is the CTE of the fetus that can clarify the exact figure. If the menstrual cycle did not have any significant disruptions, using ultrasound diagnostics, the doctor will only compare the indicators with each other. Despite the above figures, based on the extremely rapid development of the embryo, the error in determining the gestational age can be up to four days, both upward and downward.

CTE measurement technique

The ideal time for measuring the CTE of the fetus is its 11th week of development.

After the 16-week period, these indicators will no longer have any meaning, since the development of the baby will be monitored on the basis of completely different indicators.

The coccygeal-parietal size is measured during the sagittal scan. In other words, the fetus is divided into two conditional symmetrical halves, and the measurement line runs from the crown to the coccyx, as indicated in the photo. In the case of the presence of intense movements of the baby, the doctor will make the necessary calculations after fixing the maximum extension of the small body.

Indicators taken using ultrasound are deciphered using a special table. This table contains the values ​​of the CTE of the fetus strictly for the weeks of the first trimester, which includes the period from 7 to 14 weeks of gestation. The proposed table of the CTE of the fetus by week in the first column, indicated by the indicator " 50th percentile", Represents the weekly average. In turn, the indicated values ​​in the first column or " 50th percentile"Indicate the minimum value, and in the last or" 95th percentile»The maximum allowable value. In any case, they are not pathological and are considered normal.

It is necessary to point out the fact that the table is intended for a doctor, and any decryption must be carried out only with him to avoid misinterpretations.

12 week - a significant period for mom

After 12 obstetric weeks the first scheduled ultrasound examination is carried out, which is accompanied by a printout of a photo of the baby. During this period, at 12 weeks, the length of the baby's nasal bone is within 3 mm. Until the last 14 weeks of the examination, it will change significantly. 12 weeks of gestation represents a unique period of fetal development. In addition to the fact that the expectant mother ceases to suffer from toxicosis, the baby's brain structure improves, the hormonal system enters into a period of active action in terms of the hypothalamic-pituitary structure.

The kidneys are filled with urine, which is excreted into the amniotic space, the intestines carry out the first single, but already coordinated contractions of their muscle walls, and after 13 weeks, starting from 11, peristaltic waves will clearly appear. 12 weeks are also characterized by a different development rate - cartilage is replaced by bone tissue, forming ossification of the fetal skeleton. This can also be seen in the photo. Not at 11 or 13 weeks of life, namely 12 - the fingers get rid of the membranes, and at 13 weeks flexion movements of the hands and the first attempts of movement appear.

After 12 weeks, the CTE of the fetus is 5.3 cm. If at 11 weeks the baby's growth was 1 mm per day, then at 13-14, from the moment of conception, he will already overcome the growth line of 2 mm. In this case, the uterus is already 9 cm wide and 12 cm long. Lying on her back, due to the pubic articulation, the expectant mother can feel its edge (this is the norm).

V Lately more and more gynecologists are of the opinion that it is at 11 weeks that the first ultrasound examination is required.

Why 11? This period is considered optimal for detecting severe defects that do not lend themselves to good diagnosis at the later stages of the baby's development: 13-14 weeks. At 11 weeks, the gestational age is better determined from the moment of conception. As a rule, gynecology considers two terms: obstetric, which is counted from the moment of the last menstruation, and the period established by the CTE of the fetus, which is written side by side in brackets. Today this is already the norm, as well as the photo of the examination of the fetus.

After 12 weeks, the expectant mother must register at the antenatal clinic in order to receive a one-time special allowance for women for early date pregnancy.

What will KTR tell you about?

With an increase in gestation by 11, 12, 13, 14 weeks, the coccygeal-parietal size also tends to a higher indicator. In this case, this is the norm. Determination of these parameters makes it possible to track, in an indirect form, the course of pregnancy from the moment of conception. That is why in the first trimester, an ultrasound scan is prescribed several times, and each session is accompanied by a printout of a photo. The size of the baby is important, indicating the dynamics of its development.

A rapid increase in the CTE of the fetus is not a pathology - this is an acceptable norm, which speaks of the expected weight of the baby up to 4 kg, which is also recorded in the photo during the ultrasound session.

Knowing about such a reaction, it is forbidden to abuse drugs (multivitamins, actovegin) of metabolic action in order to avoid the birth of a "hero", whose output will be provided by a cesarean section.

Despite the fact that the weight of a baby of 4 kg or more is the norm, this also happens - the baby will not come out on its own through the birth canals. To avoid injury to the baby, the loss of a woman in labor, it is better to insist on surgical intervention, or the doctors themselves must offer such a method for the appearance of a child.

In generic practice, it is also possible when the size of the fetus at 13 and 14 weeks decreases in terms. In other words, the CTE of the fetus deviates downward, which is clearly recorded in the photo, and the norm, even an approximate one, is no longer displayed. In this case, such options are possible:

1. obstetric term is not defined correctly. With late ovulation, fertilization could also occur much later. This option is possible. Then, after even 14 weeks, the size of the baby will be acceptable, but different. To confirm the version, a secondary examination is appointed after 7-10 days, which should determine the accuracy of the dynamics;
2. undeveloped pregnancy or death of the embryo / fetus. If, after such a long period from the moment of conception, cardiac contractions or physical activity are not observed, scraping of the uterine cavity with complete removal of the fetus is necessary. Tightening with rendering medical care fraught with infertility, or a threat to life for a pregnant woman;
3. hormonal deficiency (mainly progesterone). It is fraught with premature termination of pregnancy. The doctor may prescribe the appropriate medications: Utrozhestan, Dyufaston.
4. infectious factor. It also affects the size of the baby from the moment of conception. It is eliminated by rational therapy within the permitted time frame.

Content

Ultrasound examination is essential throughout the entire period of gestation. After the first scan, a lot of new incomprehensible information becomes available to the parents-to-be. CTE is one of the ultrasound parameters that accurately determines the gestational age. Also, using this value, you can identify possible deviations in the development of the fetus.

Definition of the concept

The coccyx-parietal size (CTE) is one of the main indicators that allow you to track the correct development of the embryo until the 14th week of pregnancy. CTE is determined during ultrasound examination. The concept denotes the distance from the highest point of the crown to the lower border of the coccyx of the fetus.

Using this value, the doctor estimates the baby's weight, gestational age, correlates the information received with the norms indicated in the table. After 14 weeks of gestation, it is problematic to determine the CTE, since the fetus becomes larger, and the ultrasound sensor cannot cover this segment. Therefore, growth and development begin to be judged by the size of individual parts of the body of the crumbs.

Coccyx-parietal size can be measured after a month has passed since conception.

CTE is measured in the first weeks of gestation, during this period it is the only coefficient that evaluates the course of pregnancy. The growth rate of the indicator and compliance with the norms in the table inform the doctor about the development of the fetus. Also important is information about the heartbeat of the baby, which can be recorded on an ultrasound scan starting from 5-6 weeks of pregnancy.

Measurement methods

CTE is determined at the first ultrasound scan performed at 12 weeks of gestation. In ultrasound scanning, the main planes are distinguished: sagittal, axial, coronary. Parietal-coccygeal size is measured by sagittal scanning in the position of full extension of the embryo's head.

The doctor needs to wait for the moment when the fetus is fully dispersed. At this second, the specialist makes a freeze frame. Then, the initial value is estimated along the line from the crown to the coccyx. The value is correlated with the norms indicated in the tables. The resulting size determines the exact duration of pregnancy, because many women have an irregular cycle or do not remember the first day of the last menstruation.

The CTE establishes the exact duration of pregnancy, the date of delivery and allows you to identify possible abnormalities in the development of the fetus. There are times when ovulation occurs later than the woman suggests, or the attachment of the egg is slightly delayed. In such situations, the actual age of the embryo turns out to be less, which reveals the CTE.

Table of norms

In the first weeks of pregnancy, all embryos grow at the same rate. Genetic differences that affect body parameters begin to manifest themselves a little later. The coccyx-parietal size does not depend on nationality, ecological situation and geographical latitude. That is why the general norms of CTE by weeks of pregnancy have been established in the table.

In the first weeks of pregnancy, there are not even fluctuations in values. Possible errors are allowed as the fetus grows. If the ultrasound machine was produced recently, then the values ​​in the ultrasound protocol will be accurate, with tenths, if not, then the numbers will be whole.

Options for deviations from normal values

Non-compliance of the CTE with the norms established in the tables is often recorded. The deviation can be either down or up. Lagging behind the norm can be physiological and pathological in nature.

An increase in the coccygeal-parietal size occurs for the following reasons:

• diabetes mellitus during pregnancy;
• rhesus conflict;
• large fruit;
• doubts about the timing of the onset of the last menstruation.

To confirm the excess of the values, the woman must re-undergo an ultrasound scan after 10 days.

A decrease in CTE is caused by the following factors:

• frozen pregnancy;
• insufficient hormonal synthesis;
• delayed fertilization;
• diseases of a genetic nature;
• infectious diseases.

Even a slight deviation of the values ​​from the norm in the table requires additional examination to find out true reason Problems.

Causes

Often, the deviation of the CTE from normal values ​​is explained by an incorrect calculation of the gestational age. The doctor will correct such a mistake by correctly determining the onset of conception. But often serious disorders are diagnosed that affect the further course of pregnancy.

One of the reasons for the delay in embryonic growth is fetoplacental insufficiency.

Too short the coccygeal-parietal size can be caused by a woman's wrong lifestyle. If a pregnant woman smokes and consumes alcoholic beverages, then the embryo develops in unhealthy conditions, which leads to a delay in its growth.

Non-developing pregnancy

The death of the embryo can be the reason for the lag of the coccygeal-parietal size from the norms in the tables. If the fetus has stopped developing, and the miscarriage has not occurred, then the CTE will correspond to the values ​​at the time of death.

In the first weeks, when it is impossible to determine the baby's heartbeat, a second scan is performed after a few days to confirm the death of the fetus. In such cases, curettage of the uterine cavity or medical termination of pregnancy is carried out. During obstetric scraping, embryonic cells are collected for genetic examination. This is necessary to establish the causes of the death of the embryo.

Late ovulation and fertilization

A strong deviation of the CTE from the norm in the table may indicate an incorrectly set date or delayed ovulation. With delayed implantation of the ovum, the values ​​will be less than normal.

To confirm this version, it is necessary to do a second screening, which is scheduled one week after the first. If there is an error in the calculation, then the CTE will increase according to the actual week of pregnancy. Further medical control will be carried out according to new data.

Hormonal imbalance

If the embryo develops, but there is a significant deviation of the CTE from the norm in the table, then the reason for this discrepancy may be a problem with hormones. With a deficiency of progesterone in the female body, fetal growth slows down in the first weeks of pregnancy.

After examining biological material future mother, and hormone therapy will be prescribed to confirm the diagnosis. Drug treatment restores the level of hormones, which helps to normalize the coccygeal-parietal size.

Infectious and genetic diseases

The presence of an infectious agent negatively affects the formation of the embryo. Pathogens cause a discrepancy between the real CTE and the norms in the tables. Therefore, pregnant women need to be examined by passing the required tests. The doctor will prescribe a therapeutic regimen based on the results obtained.

Usually in the presence of pathological abnormalities at the genetic level, pregnancy terminates spontaneously in the first weeks.

Another reason for the slowdown in growth rates is chromosomal diseases: cider Patau, Down, Edwards. To accurately identify pathologies, it is required to undergo additional biochemical studies, donate DNA markers.

Pathology of the uterus

Diseases of the genital organ affect the non-compliance of the CTE with the standards established in the tables. The following pathological conditions of the uterus lead to a change in values:

• fibroids, in which the ovum cannot fully develop;
• endometrial insufficiency, which develops as a result of miscarriages, abortions;
• cervical erosion;
• ectropion - inversion of the cervix into the vaginal area, which increases the risk of miscarriage.

Anomalies in the development of a woman's internal organs also change the indicators, therefore, such patients are carefully examined to prevent all kinds of risks in a timely manner.

Additional examination

If the coccygeal-parietal size does not correspond to the norms in the table, a second ultrasound will be required. In addition to scanning, expectant mothers are offered:

• amniocentesis - the collection of amniotic fluid by puncture;
• cordocentesis - taking blood from the umbilical cord;
• chorionic villus sampling- a method for detecting congenital anomalies from cells taken from tissues that do not affect the placenta.

Since the described diagnostic methods are invasive, the written consent of the expectant mother is required for their implementation.

There is also a non-invasive option - a prenatal DNA test, which requires a woman's venous blood. In the biological material of the mother, the baby's erythrocytes are detected, from which DNA crumbs are isolated, and the likelihood of malformations is established. A similar study is carried out from the 8th week of pregnancy.

The CTE of the fetus is an important indicator that allows you to determine the exact duration of pregnancy and identify possible pathologies. Inconsistency of the indicator with the norm in the table requires additional surveys.