What to do if the TVP is more than 6 mm. Increased TVP

Prenatal screening is a combined biochemical and ultrasound examination, consisting of a blood test to determine the level of the main pregnancy hormones and a conventional ultrasound of the fetus with the measurement of several values.

First screening or “double test” (at 11-14 weeks)

Screening includes two stages: undergoing an ultrasound and drawing blood for analysis.

During an ultrasound examination, the diagnostician determines the number of fetuses, the gestational age and takes the dimensions of the embryo: CTE, BPR, size of the cervical fold, nasal bone, etc.

According to these data, we can say how correctly the baby develops in the womb.

Ultrasound screening and its norms

Assessment of the size of the embryo and its structure. Coccygeal-parietal size (CTR)- this is one of the indicators of embryo development, the size of which corresponds to the gestational age.

KTR is the size from the tailbone to the crown, excluding the length of the legs.

There is a table of normative KTE values according to the week of pregnancy (see Table 1).

Table 1 - Norm KTE according to gestational age

An upward deviation in the size of the fetus from the norm indicates the rapid development of the baby, which is a harbinger of gestation and birth of a large fetus.

The size of the fetal body is too small, indicating:

the gestational age was initially incorrectly determined by the local gynecologist, even before the visit to the diagnostician;
developmental delay as a result of hormonal deficiency, infectious disease or other ailments in the child’s mother;
genetic pathologies of fetal development;
intrauterine fetal death (but only on condition that fetal heartbeats are not audible).

Biparietal size (BDS) of the fetal head is an indicator of the baby’s brain development, measured from temple to temple. This value also increases in proportion to the duration of pregnancy.

Table 2 - Norm of fetal head BDP at a certain stage of pregnancy

Exceeding the norm of BPR of the fetal head may indicate:

a large fruit, if the other sizes are also above normal for a week or two;
abrupt growth of the embryo, if the remaining dimensions are normal (in a week or two all parameters should level out);
the presence of a brain tumor or cerebral hernia (pathologies incompatible with life);
hydrocephalus (dropsy) of the brain due to an infectious disease in the expectant mother (antibiotics are prescribed and, with successful treatment, pregnancy is maintained).

The biparietal size is less than normal in the case of underdevelopment of the brain or the absence of some of its parts.

The thickness of the collar space (TVP) or the size of the “neck fold”- this is the main indicator that, if deviated from the norm, indicates a chromosomal disease (Down syndrome, Edwards syndrome or another).

In a healthy child, at the first screening, TVP should not be more than 3 mm (for ultrasound performed through the abdomen) and more than 2.5 mm (for vaginal ultrasound).

The value of TVP in itself does not mean anything, it is not a death sentence, it is simply a risk. We can talk about a high probability of developing chromosomal pathology in the fetus only in the case of poor results of a blood test for hormones and when the size of the cervical fold is more than 3 mm. Then, to clarify the diagnosis, a chorionic villus biopsy is prescribed to confirm or refute the presence of chromosomal pathology of the fetus.

Table 3 - TVP norms by week of pregnancy

Nose bone length. In a fetus with a chromosomal abnormality, ossification occurs later than in a healthy fetus, therefore, in case of developmental abnormalities, the nasal bone is either absent at the first screening (at 11 weeks) or its size is too small (from 12 weeks).

The length of the nasal bone is compared with the standard value from the 12th week of pregnancy; at 10-11 weeks the doctor can only indicate its presence or absence.

If the length of the nasal bone does not correspond to the period of pregnancy, but other indicators are normal, there is no cause for concern.
Most likely, this is an individual feature of the fetus, for example, such a baby’s nose will be small and snub-nosed, like his parents or one of his close relatives, for example, his grandmother or great-grandfather.

Table 4 - Normal length of the nasal bone

Also, at the first ultrasound screening, the diagnostician notes whether the bones of the cranial vault, butterfly, spine, limb bones, anterior abdominal wall, stomach, and bladder are visualized. At this stage, the indicated organs and parts of the body are already clearly visible.

Assessment of fetal vital activity. In the first trimester of pregnancy, the vital activity of the embryo is characterized by cardiac and motor activity.

Since fetal movements are usually periodic and barely distinguishable at this stage, only the heart rate of the embryo has diagnostic value, and motor activity is simply noted as “determined.”

Heart rate (HR) the fetus, regardless of gender, at 9-10 weeks should be in the range of 170-190 beats per minute, from the 11th week until the end of pregnancy - 140-160 beats per minute.

Fetal heart rate below normal (85-100 beats/min) or above normal (more than 200 beats/min) is an alarming sign, in which additional examination and, if necessary, treatment are prescribed.

Study of extraembryonic structures: yolk sac, chorion and amnion. Also, the ultrasound diagnostician in the screening ultrasound protocol (in other words, in the ultrasound results form) notes data on the yolk sac and chorion, on the appendages and walls of the uterus.

Yolk sac- this is an organ of the embryo, which until the 6th week is responsible for the production of vital proteins, plays the role of the primary liver, circulatory system, and primary germ cells.

In general, the yolk sac performs various important functions up to the 12-13th week of pregnancy, after which there is no need for it, because the fetus is already developing separate organs: liver, spleen, etc., which will take on all the responsibilities for ensuring vital functions. .

By the end of the first trimester, the yolk sac shrinks in size and turns into a cystic formation (yolk stalk), which is located near the base of the umbilical cord. Therefore, at 6-10 weeks the yolk sac should be no more than 6 mm in diameter, and after 11-13 weeks, normally it is not visualized at all.

But everything is purely individual, the main thing is that it does not complete its functions ahead of schedule, so by 8-10 weeks it should be at least 2 mm (but not more than 6.0-7.0 mm) in diameter.

If before the 10th week the yolk sac is less than 2 mm, then this may indicate a non-developing pregnancy or a lack of progesterone (then Duphaston or Utrozhestan is prescribed), and if at any time in the first trimester the diameter of the yolk sac is more than 6-7 mm, then this indicates the risk of developing pathologies in the fetus.

Chorion- This is the outer shell of the embryo, covered with many villi that grow into the inner wall of the uterus. In the first trimester of pregnancy, the chorion provides:

feeding the fetus with necessary substances and oxygen;
removal of carbon dioxide and other waste products;
protection against the penetration of viruses and infections (although this function is not durable, but with timely treatment the fetus does not become infected).

Within normal limits, the localization of the chorion is “at the bottom” of the uterine cavity (on the upper wall), on the front, back or one of the side walls (left or right), and the structure of the chorion should not be changed.

The location of the chorion in the area of the internal pharynx (the transition of the uterus to the cervix), on the lower wall (at a distance of 2-3 cm from the pharynx) is called chorion presentation.

But such a diagnosis does not always indicate placenta previa in the future; usually the chorion “moves” and is firmly fixed higher.

Chorionic presentation increases the risk of spontaneous miscarriage, so with this diagnosis, stay in bed, move less and do not overwork. There is only one treatment: lie in bed for days (getting up only to go to the toilet), from time to time raising your legs up and remaining in this position for 10-15 minutes.

By the end of the first trimester, the chorion will become the placenta, which will gradually “mature” or, as they also say, “grow old” until the end of pregnancy.

Up to 30 weeks of pregnancy – degree of maturity 0.

This assesses the ability of the placenta to provide the child with everything necessary at each stage of pregnancy. There is also the concept of “premature aging of the placenta,” which indicates a complication of pregnancy.

Amnion- This is the inner water membrane of the embryo in which amniotic fluid (amniotic fluid) accumulates.

The amount of amniotic fluid at 10 weeks is about 30 ml, at 12 weeks - 60 ml, and then it increases by 20-25 ml per week, and at 13-14 weeks it already contains about 100 ml of water.

When examining the uterus by an ophthalmologist, increased tone of the uterine myometrium (or hypertonicity of the uterus) may be detected. Normally, the uterus should not be in good shape.

Often in the ultrasound results you can see the entry “local thickening of the myometrium along the posterior/anterior wall,” which means both a short-term change in the muscular layer of the uterus due to the pregnant woman’s feeling of agitation during the ultrasound, and increased uterine tone, which is a threat of spontaneous miscarriage.

The cervix is also examined; its os should be closed. The length of the cervix at 10-14 weeks of pregnancy should be about 35-40 mm (but not less than 30 mm for primiparas and 25 mm for multiparas). If it is shorter, then this indicates the risk of premature birth in the future. Approaching the day of the expected birth, the cervix will shorten (but should be at least 30 mm by the end of pregnancy), and before the birth itself, its pharynx will open.

Deviation from the norm of some parameters during the first screening does not give cause for concern; it’s just that future pregnancies should be monitored more closely, and only after the second screening can we talk about the risk of developing defects in the fetus.

Standard ultrasound protocol in the first trimester

Biochemical screening (“double test”) and its interpretation

Biochemical screening of the first trimester involves determining two elements contained in a woman’s blood: the level of free b-hCG and plasma protein-A - PAPP-A. These are two pregnancy hormones and with normal development of the baby they should correspond to the norm.

Human chorionic gonadotropin (hCG) consists of two subunits - alpha and beta. Free beta-hCG is unique in its own way, so its value is taken as the main biochemical marker used to assess the risk of chromosomal pathology in the fetus.

Table 5 - Norm of b-hCG during pregnancy by week

An increase in the value of free b-hCG indicates:

the risk of having Down syndrome in the fetus (if the norm is twice as high);
multiple pregnancy (hCG level increases in proportion to the number of fetuses);
the pregnant woman has diabetes mellitus;
gestosis (i.e. with increased blood pressure + edema + detection of protein in the urine);
fetal malformations;
hydatidiform mole, choriocarcinoma (a rare type of tumor)

A decrease in beta-hCG value indicates:

the risk of having Edwards syndrome (trisomy 18) or Patau syndrome (trisomy 13) in the fetus;
threat of miscarriage;
fetal developmental delay;
chronic placental insufficiency.

PAPP-A– pregnancy-associated plasma protein-A.

Table 6 - PAPP-A norm during pregnancy by week

A reduced level of PAPP-A in the blood of a pregnant woman gives good reason to assume that there is a risk:

development of chromosomal pathology: Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), Patai syndrome (trisomy 13) or Cornelia de Lange syndrome;
spontaneous miscarriage or intrauterine fetal death;
fetoplacental insufficiency or fetal malnutrition (i.e. insufficient body weight due to malnutrition of the baby);
development of preeclampsia (assessed together with the level of placental growth factor (PLGF). A high risk of developing preeclampsia is indicated by a decrease in PAPP-A together with a decrease in placental growth factor.

Increased PAPP-A may occur if:

a woman is carrying twins/triplets;
the fetus is large and the placenta mass is increased;
the placenta is located low.

For diagnostic purposes, both indicators are important, so they are usually considered in combination. So, if PAPP-A is reduced and beta-hCG is increased, there is a risk of the fetus having Down syndrome, and if both indicators are reduced, there is a risk of Edwards syndrome or Patau syndrome (trisomy 13).

After the 14th week of pregnancy, a test for PAPP-A is considered uninformative.

Second screening of the second trimester (at 16-20 weeks)

II screening, as a rule, is prescribed in case of deviations in screening I, less often when there is a threat of miscarriage. If there are no deviations, a second comprehensive screening can be omitted, but only an ultrasound scan of the fetus can be performed.

Ultrasound screening: norms and deviations

Screening ultrasound at this stage is aimed at determining the “skeletal” structure of the fetus and the development of its internal organs.
Fetometry. The diagnostician notes the presentation of the fetus (breech or cephalic) and takes other indicators of fetal development (see Table 7 and 8).

Table 7 - Standard fetal sizes according to ultrasound

As with the first screening, the length of the nasal bone is measured in the second. If other indicators are normal, deviation of the length of the nasal bone from the norm is not considered a sign of chromosomal pathologies in the fetus.

Table 8 - Normal length of the nasal bone

According to the measurements taken, one can judge the true gestational age.

Fetal anatomy. An ultrasound specialist examines the baby’s internal organs.

Table 9 - Normative values of the fetal cerebellum by week

The dimensions of both the lateral ventricles of the brain and the cistern magna of the fetus should not exceed 10-11 mm.

Usually other indicators, such as: Nasolabial triangle, Eye sockets, Spine, 4-chamber section of the heart, Section through 3 vessels, Stomach, Intestines, Kidneys, Bladder, Lungs - in the absence of visible pathologies are marked as “normal”.

The place of attachment of the umbilical cord to the anterior abdominal wall and to the center of the placenta is considered normal.

Abnormal attachment of the umbilical cord includes marginal, shell and split, which leads to difficulties in the birth process, fetal hypoxia and even its death during childbirth, if a planned CS is not prescribed or in case of premature birth.

Therefore, in order to avoid fetal death and blood loss in a woman during childbirth, a planned caesarean section (CS) is prescribed.

There is also a risk of developmental delay, but with normal indicators of the baby’s development and careful monitoring of the woman in labor, everything will go well for both.

Placenta, umbilical cord, amniotic fluid. The placenta is most often located on the back wall of the uterus (the form may specify more on the right or left), which is considered the most successful attachment, since this part of the uterus is best supplied with blood.

The area closer to the bottom also has a good blood supply.

But it happens that the placenta is localized on the anterior wall of the uterus, which is not considered something pathological, but this area is subject to stretching as the baby grows inside the womb, plus active movements of the baby - all this can lead to placental abruption. In addition, placenta previa is more common in women with an anterior placenta.

This is not critical, just this information is important for making a decision about the method of delivery (whether a cesarean section is necessary and what difficulties may arise during childbirth).

Normally, the edge of the placenta should be 6-7 cm (or more) above the internal os. Its location in the lower part of the uterus in the area of the internal pharynx, partially or completely blocking it, is considered abnormal. This phenomenon is called “placenta previa” (or low placentation).

It is more informative to measure the thickness of the placenta after the 20th week of pregnancy. Until this time, only its structure is noted: homogeneous or heterogeneous.

From 16 to 27-30 weeks of pregnancy, the structure of the placenta should be unchanged and homogeneous.

A structure with an expansion of the intervillous space (IVS), echo-negative formations and other types of abnormalities negatively affects the nutrition of the fetus, causing hypoxia and developmental delay. Therefore, treatment with Curantil (normalizes blood circulation in the placenta), Actovegin (improves oxygen supply to the fetus) is prescribed. With timely treatment, babies are born healthy and on time.

After 30 weeks, there is a change in the placenta, its aging, and, as a result, heterogeneity. In the later stages, this is already a normal phenomenon and does not require additional examinations or treatment.

Normally, up to the 30th week, the degree of maturity of the placenta is “zero”.

The amount of amniotic fluid. To determine their quantity, the diagnostician calculates the amniotic fluid index (AFI) according to measurements taken during an ultrasound.

Table 10 - Norms of amniotic fluid index by week

Find your week of pregnancy in the first column. The second column indicates the normal range for a given period. If the AFI indicated by the ultrasound specialist in the screening results is within this range, then the amount of amniotic fluid corresponds to the norm; less than the norm means early oligohydramnios, and more means polyhydramnios.

There are two degrees of severity: moderate (minor) and severe (critical) oligohydramnios.

Severe oligohydramnios threatens abnormal development of the fetal limbs, spinal deformation, and the baby’s nervous system also suffers. As a rule, children who have suffered oligohydramnios in the womb are delayed in development and weight.

In case of severe oligohydramnios, drug treatment must be prescribed.

Moderate oligohydramnios usually does not require treatment, you just need to adjust your diet, minimize physical activity, and take a vitamin complex (it must include vitamin E).

If there are no infections, preeclampsia or diabetes mellitus in the mother of the child, and if the baby is developing within normal limits, there is no reason to worry; most likely, this is a feature of the course of this pregnancy.

Normally, the umbilical cord has 3 vessels: 2 arteries and 1 vein. The absence of one artery can lead to various pathologies in the development of the fetus (heart defects, esophageal atresia and fistula, fetal hypoxia, disruption of the genitourinary or central nervous system).

But we can talk about the normal course of pregnancy, when the work of the missing artery is compensated by the existing one:

normal results of blood tests for hCG, free estriol and AFP, i.e. in the absence of chromosomal pathologies;
good indicators of fetal development (according to ultrasound);
the absence of defects in the structure of the fetal heart (if an open functional oval window is detected in the fetus, there is no need to worry, it usually closes up to a year, but it is necessary to be observed by a cardiologist once every 3-4 months);
undisturbed blood flow in the placenta.

Babies with such an anomaly as a “single umbilical artery” (abbreviated as EAP) are usually born with low weight and can often get sick.

Up to a year, it is important to monitor changes in the child’s body; after a year of the baby’s life, it is recommended to thoroughly take care of his health: organize a proper balanced diet, take vitamins and minerals, perform immunity-strengthening procedures - all this can bring the condition of the little body in order.

Cervix and walls of the uterus. If there are no deviations, the ultrasound examination report will indicate “Cervix and walls of the uterus without features” (or abbreviated w/o).

The length of the cervix in this trimester should be 40-45 mm, 35-40 mm is acceptable, but not less than 30 mm. If there is its opening and/or shortening compared to the previous ultrasound measurement or softening of its tissues, which is generally called “isthmic-cervical insufficiency” (ICI), then the installation of an obstetric unloading pessary or suturing is prescribed to maintain the pregnancy and reach the desired term.

Visualization. Normally it should be “satisfactory”. Visualization is difficult when:

inconvenient position of the fetus for examination (the baby is simply positioned in such a way that not everything can be seen and measured, or he was constantly spinning during the ultrasound);
overweight (in the visualization column the reason is indicated - due to subcutaneous fatty tissue (SFA));
edema in the expectant mother
hypertonicity of the uterus during ultrasound.

Standard ultrasound protocol in the second trimester

Biochemical screening or “triple test”

Biochemical screening of blood in the second trimester is aimed at determining three indicators - the level of free b-hCG, free estriol and AFP.

Free beta-hCG rate look at the table below, and you will find a transcript, it is similar at each stage of pregnancy.

Table 11 - Free b-hCG rate in the second trimester

Free estriol is one of the pregnancy hormones that reflects the functioning and development of the placenta. During the normal course of pregnancy, it grows progressively from the first days of the formation of the placenta.

Table 12 – Norm of free estriol by week

An increase in the amount of free estriol in the blood of a pregnant woman is observed during multiple pregnancies or high fetal weight.

A decrease in estriol levels is observed in cases of fetoplacental insufficiency, threatened miscarriage, hydatidiform mole, intrauterine infection, adrenal hypoplasia or anencephaly (neural tube development defect) of the fetus, Down syndrome.

A decrease in free estriol by 40% or more from the normative value is considered critical.

Taking antibiotics during the test period can also affect the decrease in estriol in a woman’s blood.

Alpha fetoprotein (AFP) is a protein produced in the liver and gastrointestinal tract of the baby, starting from the 5th week of pregnancy from conception.

This protein enters the mother's blood through the placenta and from the amniotic fluid, and begins to increase in it from the 10th week of pregnancy.

Table 13 - AFP norm by week of pregnancy

If during pregnancy a woman suffered from a viral infection and the baby suffered liver necrosis, then an increase in AFP in the pregnant woman’s blood serum is also observed.

Third screening (at 30-34 weeks)

In total, two screenings are performed during pregnancy: in the first and second trimesters. In the third trimester of pregnancy, a final monitoring of the health of the fetus is carried out, its position is examined, the functionality of the placenta is assessed, and a decision is made on the method of delivery.

For this purpose, around 30-36 weeks, an ultrasound of the fetus is prescribed, and from 30-32 weeks, cardiotocography (abbreviated as CTG - registration of changes in the cardiac activity of the fetus depending on its motor activity or contractions of the uterus).

Doppler ultrasound may also be prescribed, which allows you to assess the strength of blood flow in the uterine, placental and great vessels of the fetus. With the help of this study, the doctor will find out whether the baby has enough nutrients and oxygen, because it is better to prevent the occurrence of fetal hypoxia than to solve health problems for the baby after birth.

It is the thickness of the placenta, along with the degree of maturity, that shows its ability to supply the fetus with everything necessary.

Table 14 - Thickness of the placenta (normal)

If the thickness decreases, a diagnosis of placental hypoplasia is made. Usually this phenomenon is caused by late toxicosis, hypertension, atherosclerosis or infectious diseases suffered by a woman during pregnancy. In any case, treatment or maintenance therapy is prescribed.

Most often, placental hypoplasia is observed in fragile miniature women, because one of the factors reducing the thickness of the placenta is the weight and physique of the pregnant woman. This is not scary, what is more dangerous is the increase in the thickness of the placenta and, as a consequence, its aging, which indicates a pathology that can lead to termination of pregnancy.

The thickness of the placenta increases with iron deficiency anemia, preeclampsia, diabetes mellitus, Rh conflict and viral or infectious diseases (previous or existing) in a pregnant woman.

Normally, gradual thickening of the placenta occurs in the third trimester, which is called aging or maturity.

Degree of placenta maturity (normal):

0 degree – up to 27-30 weeks;
1st degree – 30-35 weeks;
2nd degree – 35-39 weeks;
3rd degree – after 39 weeks.

Early aging of the placenta is fraught with a deficiency of nutrients and oxygen, which threatens fetal hypoxia and developmental delays.

The amount of amniotic fluid also plays an important role in the third trimester. Below is a standard table for the amniotic fluid index - a parameter characterizing the amount of water.

Below is a table of standard fetal sizes by week of pregnancy. The baby may not correspond slightly to the specified parameters, because all children are individual: some will be large, others will be small and fragile.

Table 16 - Standard fetal sizes according to ultrasound for the entire period of pregnancy

Preparing for a screening ultrasound

Transabdominal ultrasound - the sensor is moved along the woman's abdominal wall, transvaginal ultrasound - the sensor is inserted into the vagina.

During a transabdominal ultrasound, a woman who is up to 12 weeks pregnant should come for diagnostics with a full bladder, drinking 1-1.5 liters of water half an hour to an hour before the visit to the ultrasound specialist. This is necessary so that a full bladder “squeezes” the uterus out of the pelvic cavity, which will make it possible to better examine it.

From the second trimester, the uterus increases in size and is clearly visualized without any preparation, so there is no need for a full bladder.

Bring a handkerchief with you to wipe off any remaining special gel from your stomach.

During transvaginal ultrasound, it is first necessary to perform hygiene of the external genitalia (without douching).

The doctor may tell you to purchase a condom at the pharmacy in advance, which is placed on the sensor for hygiene purposes, and to go to the toilet to urinate if the last urination was more than an hour ago. To maintain intimate hygiene, take with you special wet wipes, which you can also purchase in advance at the pharmacy or in the appropriate department of the store.

Transvaginal ultrasound is usually performed only in the first trimester of pregnancy. With its help, you can detect a fertilized egg in the uterine cavity even before the 5th week of pregnancy; an abdominal ultrasound is not always possible at such an early stage.

The advantage of vaginal ultrasound is that it can detect ectopic pregnancy, the threat of miscarriage due to pathology of the placenta, diseases of the ovaries, fallopian tubes, uterus and its cervix. Also, a vaginal examination makes it possible to more accurately assess how the fetus is developing, which can be difficult to do in overweight women (with folds of fat on the abdomen).

For ultrasound examination, it is important that gases do not interfere with the examination, therefore, in case of flatulence (bloating), it is necessary to take 2 tablets of Espumisan after each meal the day before the ultrasound, and in the morning on the day of the examination, drink 2 tablets of Espumisan or a bag of Smecta, diluting it halfway glass of water.

Preparation for biochemical screening

Blood is taken from a vein, preferably in the morning and always on an empty stomach. The last meal should be 8-12 hours before sampling. On the morning of blood sampling, you can drink only mineral water without gas. Remember that tea, juice and other similar liquids are also food.

Cost of comprehensive screening

If routine ultrasound examinations in city antenatal clinics are most often carried out for a small fee or completely free of charge, then conducting prenatal screening is an expensive set of procedures.

Biochemical screening alone costs from 800 to 1600 rubles. (from 200 to 400 UAH) depending on the city and the “plus” laboratory, you also need to pay somewhere around 880-1060 rubles for a regular ultrasound of the fetus. (220-265 UAH). In total, comprehensive screening will cost at least 1,600 – 2,660 rubles. (420-665 UAH).

It makes no sense to conduct prenatal screening at any stage of pregnancy if you are not ready to have an abortion if doctors confirm that the fetus has mental retardation (Down syndrome, Edwards syndrome, etc.) or defects of any organs.

Comprehensive screening is intended for early diagnosis of pathologies in the intrauterine development of the fetus, in order to be able to produce only healthy offspring.

TVP at 13 weeks - norm and definition. One of the most important parameters that change during the first ultrasound (planned) is TVP. The assessment of this indicator is, although not 100 percent, a fairly accurate method for early diagnosis of the presence of chromosomal abnormalities and other defects in fetal development.

TVP can be deciphered as “thickness of the collar space.” In another way, the nuchal space is called the cervical fold; it is an accumulation of fluid under the skin of the unborn child in the back of his neck. The norm of TVP at 12 weeks is not the most important, however, not the least important indicator indicating the normal development of the baby. After approximately 14 weeks of gestation, the subcutaneous fluid begins to be gradually absorbed by the child’s lymphatic system, and therefore the measurement of this parameter loses its significance.

The norm of TVP at 13 weeks is determined by ordinary ultrasound, however, in some cases, a pregnant woman needs to undergo a vaginal ultrasound. The doctor measures the length of the child's body, as well as TVP. Taking into account the data obtained, he can draw preliminary conclusions about the development of the fetus. Please note that the results of a regular and vaginal examination usually give different indicators. This is explained by the fact that different devices “see” the child differently.

Why is the collar area measured? Is it possible to make an accurate diagnosis based on the TVP value?

Specifically, deviations from normal TVP values at the 11th week of pregnancy do not yet indicate the presence of any fetal pathology. This show is measured to determine the risk group. It is likely that the child requires additional testing to determine whether Down syndrome is present. The thickened collar space does not indicate anything at all.

According to statistics, only 7 percent of children whose TVP at 11 weeks differed from normal values were born with Down syndrome. If you have been prescribed an additional examination, do not worry, because this is not a death sentence for the child!

What should the TVP indicators be? The norm is 11 weeks.

At a period of 11 weeks, the unborn child’s size does not exceed 50–60 millimeters, and the norm of TVP should be 1–2 millimeters; similar parameters remain at 12 weeks. But at the 13th week of gestation, when TVP already matters, its indicator increases to approximately 2.8 - 3 millimeters. In the case when TVP exceeds 3 millimeters, this is considered a deviation from the norm. In such a situation, the pregnant woman is sent for examination.

To confirm that a child has Down syndrome, it is not enough to simply measure TVP. You will also need to undergo a triple test, chorionic villus sampling and other tests. When performing a transvaginal ultrasound, the rate of TVP at 11 weeks should not exceed 1.8 millimeters, and at 13 weeks - 2.5 millimeters.

Even if you have undergone several tests, and they all confirmed your fears about a thickened nuchal translucency, you cannot yet say for sure that your baby has Down syndrome. Amniocentesis is considered the only accurate diagnostic option, but it is not advisable to carry it out before the 16th week of gestation. In rare cases, the TVP value exceeds 4 - 5 millimeters. However, even with such indicators, at 11 weeks there is a chance to give birth to a completely healthy baby (in 50 percent of cases). The main thing is not to imagine all sorts of horrors and not to panic, since stress is harmful both for the expectant mother and for the unborn baby.

Diagnostics and norm

Normally, TVP is less than 3 mm

Diagnosis is carried out using. This is an absolutely safe procedure for mother and child. Ultrasound examination is used several times during pregnancy and is safe at any stage.

The normal thickness of the nuchal translucency ranges from 0.7 to 2.7 mm, depending on what week of pregnancy the screening is performed. The collar space reaches its maximum size at the 14th week, and then begins to decrease.

The reliability of the procedure depends on many factors: the professionalism of the doctor, equipment, correctly determined gestational age, location of the fetus, etc.

The ultrasound procedure itself to determine TVP takes place in several stages:

performed either transvaginally or abdominally. If this is a transvaginal ultrasound, it is recommended that you go to the toilet and empty your bladder before the procedure.
Abdominal ultrasound requires reverse preparation. To better examine the fetus, a full bladder is necessary, so half an hour before the procedure, the woman is recommended to drink a couple of glasses of clean still water and not urinate during this time. With an abdominal ultrasound, the examination is performed through the abdominal wall. The gel is applied to the skin of the abdomen. The doctor places a sensor and moves it over the abdomen, applying light pressure.
During a transvaginal ultrasound, the woman undresses to the waist and lies on the couch on her back. The knees must be bent and apart. A special elongated ultrasound probe with a protective disposable attachment is lubricated with gel and inserted shallowly into the vagina. There should be no unpleasant or painful sensations. If you experience pain in the lower abdomen, you must inform your doctor. A small amount of blood on the sensor is considered normal. The blood will stop smearing throughout the day.

The result is given to the patient in the form of a completed ultrasound form. It must be taken to a doctor. Biochemical screening is usually ready within a few days.

Chromosomal causes of increased TVP

With an increased TVP, a woman is included in the risk group. The more the norm is exceeded, the greater the likelihood of developing a chromosomal abnormality in the child. It is worth remembering that we are talking about probability, that is, a guarantee that a child has a pathology is not always given.

Screening is carried out only after informing the woman. She can voluntarily refuse the examination.

If we talk about the chromosomal causes of increased thickness of the nuchal translucency, then both trisomy (an extra chromosome) and monosomy (the absence of one chromosome) are probable.

Some of the chromosomal abnormalities that can be identified through screening include:

Down syndrome. This is one of the most common chromosomal abnormalities, accompanied by the appearance of an extra chromosome. The causes of this pathology are difficult to determine; the risk group includes women over 35 years of age and older primigravidas. Children with Down syndrome have characteristic appearance features: a round flat face, slanted eyes, small ears, short fingers. These children are also characterized by mental retardation and muscle weakness.
Patau syndrome. In this disease, chromosome 13 is copied. The survival rate of children with Patau syndrome is quite low. There is a high probability of intrauterine death. After birth, more than 90% of children with this pathology die before one year. Characteristic symptoms are multiple malformations, heart defects, hydrocephalus or microcephaly, cleft lip, cleft palate.
Turner syndrome. In this disease, one X chromosome is missing. The risk of this pathology has nothing to do with the age of the mother. Children with Turner syndrome have severe sexual infantilism, a short neck, joint deformities, and heart defects are often found. Intelligence is usually preserved, but mental retardation also occurs.

If a child has Down syndrome, the woman is given a choice: terminate the pregnancy or continue it. If the chromosomal abnormality is incompatible with life, abortion is recommended.

Other reasons for deviation from the norm

The thickness of the nuchal translucency is not always associated with a chromosomal abnormality. We can talk about pathology only based on the results of ultrasound and biochemical screening in general. In some cases, the reasons for the deviation of TVP from the norm may be other pathologies of fetal development, as well as the state of the mother’s body.

The most common reasons for increased TVP are:

Heart defects. Serious heart defects can be detected during the first screening. If they are incompatible with life, doctors recommend terminating the pregnancy, but in some cases treatment is possible. If the mother refuses an abortion, but the defect is serious, most likely the pathology will lead to intrauterine death.
Anomalies of connective and bone tissue. Various deviations in the formation of connective and bone tissue, leading to skeletal deformation, can be determined in the initial stages of pregnancy.
. If CMV enters the body of a pregnant woman, the likelihood of infecting the fetus is very high. If infection occurs during pregnancy, the virus begins to affect the development of the fetus, causing various abnormalities, causing stillbirth, intrauterine death, and miscarriages. After birth, the child may develop pneumonia, deafness, and often have heart defects.
. This disease is transmitted through contact with domestic animals and is only dangerous if infected during pregnancy. If a woman becomes infected in the first trimester, the probability of developing malformations incompatible with life is about 20%.

More information about Down syndrome can be found in the video:

After identifying the pathology, further examination is prescribed: collection of amniotic fluid for examination, collection of placental cells and embryonic villi. These procedures provide more reliable information regarding existing deviations.

The choice regarding termination of pregnancy always remains with the parents. Doctors can recommend, but cannot force, a pregnant woman to undergo an abortion.

Scheduled ultrasounds during pregnancy for a woman are not only a joyful “meeting” with the baby, but also worries, anxieties, and fears. Expectant mothers hang on every word of the doctor, often getting scared when they hear new terms. Today we will talk about an important indicator - the thickness of the fetal collar space. Its measurement during an ultrasound examination is a mandatory procedure, so you should not be afraid of it. The measurements taken by the ultrasound doctor can become a cause for concern for the expectant mother. What indicators indicate a deviation from the norm and what to do about it, you will learn in the article.

What is the collar space?

So, what is the nuchal space in the fetus? This is an ultrasound marker that can be used to suspect a chromosomal pathology in a baby. Its thickness (abbreviated TVP) is the width of the space in the child’s cervical spine filled with subcutaneous fluid. The term “nuchal translucency” was proposed in 1996, and the marker itself is used for screening in almost all developed countries of the world.

The study of the fetal collar zone is carried out between 11 and 13 weeks of pregnancy, that is, during the first pregnancy. Only during this period will it be informative. Before the 11th week, the study is not carried out, since at this time the fetus is still very small. Starting from the 14th week, the liquid will be absorbed by the baby’s lymphatic system, and this indicator is no longer of value to the diagnostician.

If you hear this term from a specialist, do not immediately panic. Every fetus normally has a nuchal space. What you need to pay attention to is its thickness. If there is a significant deviation from the norm, the doctor may suspect that the baby has Down syndrome. However, an increase in the collar zone alone is not enough for an accurate diagnosis.

TVP norms

The thickness of the cervical collar zone in the fetus can be determined using both transabdominal ultrasound - in which the sensor is located on the anterior abdominal wall of the woman, and transvaginal examination - here a special vaginal sensor is used. Most often, a transabdominal ultrasound is performed, and a vaginal probe is used if the first method does not allow assessment of the fetal structures. Some specialists may use a combination of methods.

According to International standards, the norm for the collar space for the period from 11 to 13 weeks is up to 3 millimeters inclusive. If there are no pathologies, then from the 14th week this indicator will decrease and disappear in the 2nd trimester of pregnancy. The greater the deviation from the norm, the higher the likelihood of developing pathology in the child.

Important: a deviation in TVP indicators is not a 100% guarantee that the baby has a pathology.

What does exceeding the norm of the collar space indicate?

As already mentioned, an increase in the nuchal space in the fetus indicates the likelihood of developing chromosomal pathologies:

in 50% of cases this is Down syndrome - a disease caused by the presence of an additional 47 chromosome, the causes of the pathology are not fully understood, but the likelihood increases if the mother’s age is less than 18 and more than 35 years old, and also if the parents are blood relatives;
25% – Edwards syndrome – the presence of a triple 18th pair of chromosomes; infants born with this pathology do not survive to one year of age in 90% of cases;
a 10% chance of developing Turner syndrome, a disease that occurs due to the absence or defects of one of the X chromosomes; this pathology often causes early miscarriages;
5% - Patau syndrome - a disease in which the 13th chromosome pair has an additional chromosome; infants with this pathology die in the first months of life in 95% of cases.

But there is also the possibility of having a completely healthy baby. You can find out the risks of a child developing pathologies in the table below.

If the indicator is 4 millimeters, the probability of an unfavorable outcome is 27%, when the indicator increases to 6 millimeters, the risk increases to 49%, but even with 9 millimeters of TVP, in 22% of cases, babies are born healthy.

What to do if TVP is elevated?

A woman should know that a study such as measuring the thickness of the fetal nuchal space is not specific. This means that if deviations from the norm are detected, it is necessary to conduct a series of tests, based on the results of which it is already possible to judge whether the child has pathologies.

Chorionic villus biopsy

If the result obtained during an ultrasound exceeds 3 millimeters, the pregnant woman is referred for a chorionic villus biopsy. What is this procedure? The placenta in the initial stages of pregnancy is called the chorion and it has the same chromosome set as the fetus. A biopsy is a study of a small piece of chorion, during which you can find out about the chromosomal composition of the baby’s cells, without affecting the baby itself. This is a very informative procedure that allows you to diagnose many chromosomal pathologies and hereditary diseases. However, it cannot be called safe, so the reasons for its implementation must be serious. The consequence of such a diagnosis in 1 case out of 100 is a miscarriage.

The most reliable result of a chorionic villus biopsy can be obtained by conducting a study in the period from 11 to 13 weeks. The timing of the manipulation may vary within 10-19 weeks. The material is collected using a long thin needle, which is punctured through the abdominal wall, or using a probe that is inserted through the cervix. The choice of method depends on the location of the placenta. After this, a piece of chorionic tissue is sent to the laboratory, the woman will learn the results in about a week.

Amniocentesis

An alternative research method is amniocentesis. This method can be used if the biopsy data was inaccurate or the chorionic tissue was destroyed in the laboratory during analysis. The essence of the method is to analyze amniotic fluid - amniotic fluid. It surrounds the baby and particles of his skin, hair, waste products get into it, examining which determines the presence of pathologies.

In the early stages of pregnancy, between 10 and 14 weeks, amniocentesis is performed very rarely, as there is a high probability of harm to the baby due to the small volume of amniotic fluid. In order to diagnose chromosomal pathologies, the analysis is carried out in the period from 17 to 22 weeks. In this case, if the results are unfavorable, the woman may agree to terminate the pregnancy.

PPAP-A analysis

Another marker of chromosomal pathologies is a blood test for PAPP-A, a protein whose synthesis is activated with the onset of pregnancy. The PPAP-A protein is present in the blood of all people, but in small quantities. In pregnant women, this protein is produced by the outer layer of cells of the embryo, with the help of which it attaches to the wall of the uterus. A woman's blood test for PPAP-A level will be most informative from 11 to 14 weeks, although it can be prescribed from 8 weeks. Analysis for PPAP-R is prescribed in combination with a test for.

If the screening results reveal that the permissible TVI norm is exceeded, most importantly, do not panic! It's worth getting re-examined. Perhaps the doctor took inaccurate measurements or the baby took an uncomfortable position. For example, the data may be unreliable if the baby’s chin was pressed tightly to the chest or, on the contrary, the head was tilted back.