Every pregnant woman is required to undergo screening, a diagnostic complex that allows for the identification of severe malformations of the embryo or its genetic pathologies in the early stages of pregnancy. Screening in the first trimester involves performing an ultrasound of the fetus and a biochemical blood test.

You can undergo prenatal screening from the first day of the 10th obstetric week of pregnancy until the 6th day of the 13th week. Typically, expectant mothers are sent for research in the period of 11-12 weeks with a slight adjustment to the accuracy of the period. Only during this period can the most reliable data on the condition of the embryo be obtained, since some of the most important indicators of its development cannot be calculated after the 14th week of pregnancy.

Who should be screened?

This procedure is necessary for all women carrying a child without exception. A pregnant woman has the right to refuse to undergo it, but this is not advisable due to the fact that there are certain risks and features of the course of pregnancy, which the supervising doctor and the woman herself should be aware of.

There are risk groups that must undergo prenatal screening:

• a history of spontaneous miscarriage, frozen or regressing pregnancy;
• all pregnant women over 34 years of age;
• presence of bad habits in a pregnant woman or the father of an unborn child;
• the presence of risk factors for early miscarriage;
• patients who have suffered from acute respiratory viral infections or other infectious diseases in the early stages, as well as the use during this period of medications that are prohibited or not recommended during pregnancy;
• presence of occupational hazards;
• hereditary pathologies in the family;
• if a woman already has a child with developmental abnormalities or in the early stages of previous pregnancies, screening has identified defects or other developmental abnormalities.

What does an ultrasound show and do you need to prepare for it?

No, no special preparation is required for this procedure. Previously, during transabdominal examinations, the woman was warned about the need to fill the bladder before the ultrasound. Modern ultrasound equipment makes it possible not to adhere to this condition, therefore, when undergoing the procedure transvaginally or transabdominally, no special preparation is required.

Ultrasound at 11-13 weeks allows you to evaluate the following indicators of embryo development:

• head circumference;
• the distance at which the parietal burs are located;
• structure and symmetry of the brain hemispheres;
• the distance between the coccyx and the parietal bone;
• the distance between the occipital and frontal bones;
• length of the bones of the lower leg and forearm;
• length of the femur and humerus;
• collar space thickness;
• location and size of large vessels and heart;
• heart rate;
• location of the stomach.

Prenatal screening allows us to judge the presence or absence of the following pathologies in the embryo:

1. Down, Smith-Opitz, Edwards, Cornelia de Lange, Patau syndromes.

2. Meningocele, encephalocele and other anomalies of the neural tube structure.

3. Omphalocele, in which some internal organs are located in the hernial sac.

4. Triploidy - multiple developmental defects that arise against the background of a genetic anomaly.

Screening can detect an ectopic, missed or regressed pregnancy. The study allows you to visualize the condition of the uterus and assess the course of pregnancy. Ultrasound screening shows the following characteristics:

· amount of water;

· presence of uterine hypertonicity (or absence thereof);

· thickness and location of the placenta;

· number of vessels in the umbilical cord.

Biochemical screening

It is carried out only after receiving the results of the ultrasound, but during the same period in which ultrasound is allowed - 11-13 weeks. Blood from a vein is donated in the morning on an empty stomach; a few days before, doctors recommend following a hypoallergenic diet so that the test results are correct.

Important elements of assessment during biochemical screening are:

· β-hCG is a hormone produced by the “shell” of the embryo;

· PAPP-A is a protein produced by the placenta.

If these indicators deviate from the norm, the risk of having the following pathologies increases:

· Down, Cornelia de Lange and Edwards syndromes;

· premature termination of pregnancy;

· placental insufficiency;

· ectopic pregnancy.

Timely completion of these studies in compliance with the necessary rules will make it possible to learn in the early stages about existing developmental anomalies in the fetus and the characteristics of the course of pregnancy.

First trimester screening in Chelyabinsk

In Chelyabinsk, you can undergo 1st trimester screening at the GIMENEY multidisciplinary medical center. 1 screening is a thorough prenatal diagnosis, which is carried out by competent specialists using modern equipment.

1st trimester screening is a diagnostic test that is carried out for pregnant women at risk from 10 to 14 weeks. It, being the first of two screening observations, allows you to determine with great accuracy how high the risk of giving birth to a sick fetus is. This examination consists of two parts - donating blood from a vein and ultrasound. Based on them, taking into account many of your individual factors, the geneticist makes his verdict.

Screening (from the English “screening”) is a concept that includes a number of activities to identify and prevent diseases. For example, screening during pregnancy provides the doctor with complete information about the various risks of pathologies and complications in the development of the child. This makes it possible to take full measures in advance to prevent diseases, including the most severe ones.

Who needs 1st trimester screening?

It is very important that the following women undergo the study:

• those who are in a consanguineous marriage with the child's father
• who have had 2 or more spontaneous abortions (premature births)
• there was a frozen pregnancy or stillbirth
• a woman has had a viral or bacterial disease during pregnancy
• have relatives suffering from genetic pathologies
• this couple already has a child with Patau, Down syndrome or others
• there was an episode of treatment with drugs that cannot be used during pregnancy, even if they were prescribed for vital signs
• pregnant for over 35 years
• Both future parents want to check the likelihood of having a sick fetus.

What to look for at the first ultrasound screening during pregnancy

What do they look at at the first screening? The length of the embryo is assessed (this is called the coccygeal-parietal size - CTR), the size of the head (its circumference, biparietal diameter, distance from the forehead to the back of the head).

The first screening shows the symmetry of the cerebral hemispheres and the presence of some of its structures that are required during this period. Also look at the 1st screening:

• long tubular bones, the length of the humerus, femur, forearm and tibia bones is measured
• Are the stomach and heart located in designated places?
• the size of the heart and the vessels emanating from them
• belly size.

What pathology does this examination reveal?

The first pregnancy screening is informative in terms of detecting:

• pathologies of the CNS rudiment - the neural tube
• Patau syndrome
• omphalocele - umbilical hernia, when a different number of internal organs are located outside the abdominal cavity, but in the hernial sac above the skin
• Down syndrome
• triploidy (triple set of chromosomes instead of double)
• Edwards syndrome
• Smith-Opitz syndrome
• de Lange syndrome.

Time frame for the study

When should you do your first screening? The diagnostic time frame for the 1st trimester is very limited: from the first day of the 10th week to the 6th day of the 13th week. It is better to do the first screening in the middle of this range, at 11-12 weeks, since an error in the calculations significantly reduces the correctness of the calculation.

Your doctor should once again carefully and thoroughly, depending on the date of your last menstruation, calculate at what time you should undergo the first study of this kind.

How to prepare for research

First trimester screening is carried out in two stages:

1. First, an ultrasound screening is done. If this is done transvaginally, then no preparation is required. If it is done abdominally, then it is necessary that the bladder is full. To do this, you need to drink half a liter of water half an hour before the test. By the way, the second screening during pregnancy is carried out transabdominally, but does not require preparation.
2. Biochemical screening. This word refers to taking blood from a vein.

Considering the two-stage nature of the study, preparation for the first study includes:

• bladder filling – before 1 ultrasound screening
• fasting at least 4 hours before taking blood from a vein.

In addition, you need a diet before diagnosing the 1st trimester in order for the blood test to give an accurate result. It consists of avoiding chocolate, seafood, meat and fatty foods the day before you plan to attend a pregnancy screening ultrasound.

If you plan (and this is the best option for perinatal diagnostics in the 1st trimester) to undergo both ultrasound diagnostics and donate blood from a vein on the same day, you need:

• throughout the previous day, deny yourself allergenic foods: citrus fruits, chocolate, seafood
• exclude completely fatty and fried foods (1-3 days before the test)
• before the test (usually blood is donated for 12-week screening before 11:00) go to the toilet in the morning, then either do not urinate for 2-3 hours, or drink half a liter of still water an hour before the procedure. This is necessary if the examination will be performed through the abdomen
• If ultrasound diagnostics are done with a vaginal probe, then preparation for 1st trimester screening will not include filling the bladder.

How the research is carried out

How is a test for developmental defects done in the 1st trimester?

It, like the 12-week examination, consists of two stages:

1. Ultrasound screening during pregnancy. It can be performed either vaginally or through the abdomen. It feels no different from an ultrasound at 12 weeks. The difference is that it is performed by sonologists who specialize specifically in prenatal diagnostics, using high-end equipment.
2. Blood sampling from a vein in the amount of 10 ml, which should be carried out on an empty stomach and in a specialized laboratory.

How is screening diagnostics performed in the 1st trimester? First, you undergo your first pregnancy ultrasound. It is usually performed transvaginally.

Read also:

Detailed Doppler ultrasound (USDG) of pregnant women

To perform the examination, you will need to undress from the waist down and lie on the couch with your legs bent. The doctor will very carefully insert a thin special sensor in the condom into your vagina and move it slightly during the examination. It is not painful, but after examining the pad that day or the next, you may notice a small amount of bloody discharge.

The video shows a 3D ultrasound during pregnancy during 1st trimester screening. How is the first screening done with a transabdominal probe? In this case, you either undress to the waist, or simply lift your clothes so as to expose your abdomen for examination. With this 1st trimester ultrasound screening, the sensor will move across the abdomen without causing pain or discomfort. How is the next stage of the examination carried out? With the results of the ultrasound examination, you go to donate blood. There you will also be given some information that is important for the correct interpretation of the results.

You will not receive results immediately, but after a few weeks. This is how the first pregnancy screening takes place.

Decoding the results

1.Normal ultrasound data

Deciphering the first screening begins with the interpretation of ultrasound diagnostic data. Ultrasound standards:

Coccygeal-parietal size (CPS) of the fetus

When screening at 10 weeks, this size is in the following range: from 33-41 mm on the first day of the 10th week to 41-49 mm on the 6th day of the 10th week.

Screening at 11 weeks - normal CTE: 42-50 mm on the first day of the 11th week, 49-58 on the 6th day.

During a 12-week pregnancy, this size is: 51-59 mm at exactly 12 weeks, 62-73 mm on the last day of this period.

2. Thickness of the collar area

Ultrasound standards of the 1st trimester in relation to this most important marker of chromosomal pathologies:

• at 10 weeks – 1.5-2.2 mm
• screening at 11 weeks is represented by the norm of 1.6-2.4
• at week 12 this figure is 1.6-2.5 mm
• at 13 weeks – 1.7-2.7 mm.

3. Nasal bone

The interpretation of the 1st trimester ultrasound necessarily includes an assessment of the nasal bone. This is a marker due to which one can assume the development of Down syndrome (this is why screening is done in the 1st trimester):

• at 10-11 weeks this bone should already be detected, but its size has not yet been assessed
• screening at 12 weeks or a week later shows that this bone is at least 3 mm normal.

4. Heart rate

• at 10 weeks – 161-179 beats per minute
• at 11 weeks – 153-177
• at 12 weeks – 150-174 beats per minute
• at 13 weeks – 147-171 beats per minute.

5. Biparietal size

The first screening study during pregnancy evaluates this parameter depending on the period:

• at 10 weeks – 14 mm
• in 11 – 17 mm
• screening at 12 weeks should show a result of at least 20 mm
• at 13 weeks, BPD averages 26 mm.

Based on the results of the 1st trimester ultrasound, it is assessed whether there are any markers of fetal development abnormalities. It also analyzes what age the baby’s development corresponds to. At the end, a conclusion is made whether the next screening ultrasound is necessary in the second trimester.

You can ask to have a video of your 1st trimester ultrasound recorded. You also have every right to receive a photo, that is, a printout of the image that is either the most successful (if everything is normal) or most clearly demonstrates the pathology found.

What hormone levels are determined by 1 screening?

First trimester screening does more than just evaluate ultrasound results. The second, no less important stage, by which it is judged whether the fetus has serious defects, is a hormonal (or biochemical) assessment (or blood test in the 1st trimester). Both of these stages constitute genetic screening.

1. Human chorionic gonadotropin

This is the hormone that colors the second line on a home pregnancy test. If screening in the first trimester reveals a decrease in its level, this indicates a pathology of the placenta or an increased risk of Edwards syndrome.

Elevated hCG during the first screening may indicate an increased risk of developing Down syndrome complex in the fetus. Although with twins this hormone is also significantly increased.

First screening during pregnancy: the level of this hormone in the blood (ng/ml):

• Week 10: 25.80-181.60
• Week 11: 17.4-130.3
• transcript of the perinatal study of the 1st trimester at week 12 regarding hCG shows a normal figure of 13.4-128.5
• at week 13: 14.2-114.8.

2. Pregnancy-associated protein A (PAPP-A)

This protein is normally produced by the placenta. Its concentration in the blood increases with increasing gestational age.

How to make sense of the data

The program, into which ultrasound diagnostic data of the first trimester is entered, as well as the level of the two above hormones, calculates the analysis indicators. These are called "risks". At the same time, the transcript of the screening results of the 1st trimester is written on the form not in terms of hormone levels, but in such an indicator as “MoM”. This is a coefficient that shows the deviation of the value for a given pregnant woman from a certain calculated median.

To calculate MoM, the indicator of a particular hormone is divided by the median value calculated for a given area for a given period of pregnancy. The MoM norms at the first screening are from 0.5 to 2.5 (for twins and triplets - up to 3.5). An ideal MoM value is close to “1”.

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Appointment at 23, 24 and 25 weeks of pregnancy in the ultrasound diagnostic room

When screening in the 1st trimester, the MoM indicator is influenced by age-related risk: that is, the comparison is made not just with the calculated median at this stage of pregnancy, but with the calculated value for a given age of the pregnant woman.

Interim screening results from the first trimester normally indicate the amount of hormones in MoM units. So, the form contains the entry “hCG 2 MoM” or “PAPP-A 1 MoM” and so on. If MoM is 0.5-2.5, this is normal.

A pathology is considered to be a hCG level below 0.5 median levels: this indicates an increased risk of Edwards syndrome. An increase in hCG above 2.5 median values ​​indicates an increased risk of Down syndrome. A decrease in PAPP-A below 0.5 MoM indicates that there is a risk for both of the above syndromes, but its increase does not mean anything.

Are there any risks in the study?

Normally, the diagnostic results of the 1st trimester end with a risk assessment, which is expressed as a fraction (for example, 1:360 for Down syndrome) for each syndrome. This fraction reads like this: in 360 pregnancies with the same screening results, only 1 baby is born with Down pathology.

Decoding the 1st trimester screening standards. If the child is healthy, the risk should be low and the screening test result should be described as “negative.” All numbers after the fraction must be large (greater than 1:380).

A poor first screening is characterized by a “high risk” entry in the report, a level of 1:250-1:380, and hormone results of less than 0.5 or more than 2.5 median values.

If the 1st trimester screening is bad, you are asked to visit a geneticist who will decide what to do:

• schedule you for a repeat study in the second, then screening in the 3rd trimester
• propose (or even insist) on invasive diagnostics (chorionic villus biopsy, cordocentesis, amniocentesis), on the basis of which the question of whether this pregnancy is worth prolonging will be decided.

What influences the results

As with any study, there are false positive results from the first perinatal study. So, with:

• IVF: hCG results will be higher, PAPP will be lower by 10-15%, the indicators of the first screening ultrasound will increase the LZR
• obesity of the expectant mother: in this case, the levels of all hormones increase, while with low body weight, on the contrary, they decrease
• 1st trimester screening for twins: the normal results for such a pregnancy are not yet known. Risk assessment is therefore difficult; Only ultrasound diagnostics is possible
• diabetes mellitus: the 1st screening will show a decrease in hormone levels, which is not reliable for interpreting the result. In this case, pregnancy screening may be canceled
• amniocentesis: the rate of perinatal diagnosis is not known if the manipulation was carried out within the next week before blood donation. It is necessary to wait longer after amniocentesis before undergoing the first perinatal screening of pregnant women.
• psychological state of the pregnant woman. Many people write: “I’m afraid of the first screening.” This can also affect the outcome in unpredictable ways.

Some features of pathology

The first pregnancy screening for fetal pathology has some features that ultrasound doctors see. Let's consider perinatal screening of trisomy as the most common pathologies detected using this examination.

1. Down syndrome

1. most fetuses do not have a visible nasal bone at 10-14 weeks
2. from 15 to 20 weeks this bone is already visualized, but it is shorter than normal
3. facial contours are smoothed
4. Doppler testing (in this case it can be carried out even at this time) reveals reverse or other pathological blood flow in the ductus venosus.

2. Edwards syndrome

1. tendency for heart rate to decrease
2. there is an umbilical hernia (omphalocele)
3. no nose bones visible
4. instead of 2 umbilical cord arteries - one

3. Patau syndrome

1. almost everyone has a rapid heartbeat
2. impaired brain development
3. slowed fetal development (discrepancy between bone lengths and period)
4. developmental disorder of certain areas of the brain
5. umbilical hernia.

Where to take the study

Where is 1st trimester screening done? Many perinatal centers, medical genetic consultations and private clinics are conducting this research. To choose where to do the screening, see if there is a laboratory in the clinic itself or next to it. It is recommended to take it in such clinics and centers.

For example, in Moscow, the Center has proven itself well: it conducts and screening for the 1st trimester can be done at this Center.

Ultrasound screening of the 1st trimester: average price – 2000 rubles. The cost of the first perinatal study (with determination of hormones) is about 4000-4100 rubles.

How much does 1st trimester screening cost by type of test: ultrasound - 2000 rubles, hCG determination - 780 rubles, PAPP-A test - 950 rubles.

Description

Determination method See individual tests

Material under study Blood serum

The test is performed for a screening examination of pregnant women to assess the risk of fetal chromosomal abnormalities: trisomy 21 (Down syndrome) and trisomy 18, 13 (Edwards syndrome, Patau syndrome). Quantitative assessment of research results is carried out using PRISCA software.

Attention! For this study, ultrasound results are required!

Biochemical screening of the first trimester of pregnancy “double test” of the first trimester consists of the following studies:

1. Free b-subunit of human chorionic gonadotropin (free b-hCG, free b-hCG), test No. 189;
2. PAPP-A (pregnancy associated protein A, plasma protein A associated with pregnancy), test No. 161.

The optimal timing of the study is 11 - 13 weeks of pregnancy.

Carrying out a comprehensive examination at 11-14 weeks of pregnancy, including ultrasound and determination of maternal serum markers (free beta subunit of hCG and PAPP-A), followed by a comprehensive software calculation of the individual risk of having a child with a chromosomal pathology, is recommended for all pregnant women by order of the Ministry of Health RF dated November 01, 2012 No. 572n (“Procedure for the provision of medical care in the field of obstetrics and gynecology”).

The PRISCA program (developed by Typolog Software, distributed by Siemens) is a program certified in the European Union (CE certification) and registered for use in the Russian Federation that supports risk calculation for screening examinations of the 1st and 2nd trimesters of pregnancy. Risk calculation is carried out using a combination of informative biochemical markers (in the 1st trimester - free beta subunit of hCG and PAPP) and ultrasound indicators (thickness of the fetal nuchal space TVP, data on visualization of the nasal bone). Extremely important for correct calculations is the accuracy of the specified individual data, the qualifications of the doctor performing the ultrasound in performing prenatal screening ultrasound measurements, as well as the quality of laboratory tests.

Preparation

It is preferable to take blood in the morning on an empty stomach, after 8-14 hours of overnight fasting (you can drink water), it is acceptable during the day 4 hours after a light meal.

On the eve of the study, it is necessary to exclude increased psycho-emotional and physical stress (sports training), alcohol intake, and smoking an hour before the study.

First trimester screening is optimal at 11-13 weeks, second trimester screening at 16-18 weeks. Ultrasound data from the first trimester can be used to calculate risk when conducting biochemical screening in the second trimester. General recommendations for preparing for research can be found.

Indications for use

Prenatal screening of pregnant women at 11-14 weeks of pregnancy to assess the risk of trisomy 21 (Down syndrome) and trisomy 13/18.

Special indications for prescribing screening studies to identify the risk of fetal chromosomal abnormalities are:

• woman's age over 35 years;
• the presence in the family of a child (or a history of the fetus of an interrupted pregnancy) with genetically confirmed Down disease, other chromosomal diseases, congenital malformations;
• hereditary diseases in close relatives;
• radiation exposure or other harmful effects on one of the spouses before conception.

To complete the study, you must fill out.

Interpretation of results

Interpretation of research results contains information for the attending physician and is not a diagnosis. The information in this section should not be used for self-diagnosis or self-treatment. The doctor makes an accurate diagnosis using both the results of this examination and the necessary information from other sources: medical history, results of other examinations, etc.

The results of the examination are issued in the form of a report form. It indicates the data used in the calculations, provides the results of the studies conducted, and the adjusted MoM values. In conclusion, quantitative risk assessment indicators are indicated for trisomy 21 (Down syndrome) and trisomy 13/18 (Patau syndrome and/or Edwards syndrome), which reflect the frequency of occurrence of the corresponding types of pathology with similar examination results and individual data. For example, a risk indicator of 1:6250 means that the statistical probability of having a child with a corresponding pathology is one case out of 6250 pregnancies with similar individual data. The PRISCA program sets conditional thresholds for identifying a high-risk group - a frequency above 1/250 for trisomy 21 (Down syndrome) and above 1/100 for trisomy 13/18.

The results of calculating the risk of fetal chromosomal abnormalities based on screening biochemical studies and ultrasound indicators are only statistical probabilistic indicators that are not the basis for making a diagnosis, but can serve as an indication for prescribing further special research methods. According to the current recommendations of the Ministry of Health of the Russian Federation, when a pregnant woman is diagnosed with a high calculated risk for chromosomal disorders in the fetus (individual risk 1/100 or higher), an obstetrician-gynecologist refers her to a medical genetic consultation (center) for medical genetic counseling and determination or confirming the diagnosis using invasive examination methods to establish the fetal karyotype.

The use of comprehensive (ultrasound TVP + biochemical tests) screening, according to a number of studies, makes it possible to detect Down syndrome in the fetus in the first trimester of pregnancy in 85 - 90% of cases with 5% of false positive results. Comprehensive screening helps to identify not only the risk of fetal chromosomal abnormalities, but also the general risk of pregnancy pathology.

When pregnancy occurs, expectant mothers begin to be overcome by fear: is everything okay with the baby? Fortunately, modern diagnostic methods allow early detection of fetal development disorders. There is such a thing as prenatal screening. This is nothing more than a set of instrumental and laboratory research methods designed to identify the risk of developing congenital pathologies.

Table of contents:

Indications for screening

We recommend reading:

There is a certain list of laboratory tests that all pregnant women should undergo. Prenatal screening is not mandatory for everyone, but only for those women who are at particular risk for congenital anomalies.

So, you should undergo screening in the following cases:

1. Pregnant woman over 35 years old;
2. If the family already has children with chromosomal abnormalities;
3. An obstetric history of two or more miscarriages;
4. If in the first trimester a woman took medications prohibited during pregnancy;
5. The child's parents are close relatives;
6. If the parent underwent radiation before conceiving a child;
7. Threat of miscarriage.

Screening studies are carried out every trimester. The greatest importance is to conduct research in the first and second trimesters.

1st trimester screening

The first screening is a screening performed in the first trimester. The most acceptable timing is 10-13 weeks of pregnancy. The first screening allows you to identify congenital malformations at an early stage.

First trimester screening includes:

• Fetal ultrasound;
• Biochemical blood test.

Ultrasound of the fetus in the first trimester

Allows you to determine the location of organs, fetal body length, head circumference, measure the thickness of the cervical fold, coccygeal-parietal size.

The coccygeal-parietal dimension (CTR) is the length measured from the coccyx to the parietal region of the skull. If, during an ultrasound, a specialist determines that the CTE is less than expected, this may indicate:

• Incorrectly calculated gestational age;
• Impaired fetal development as a result of hormonal and infectious diseases of the mother;
• The presence of gene pathology;
• Incorrect position of the fetus, which does not allow you to fully measure the distance.

Measuring an indicator such as biparietal size (BPD) allows us to study the formation of the brain. Biparietal size is the distance from one temple to another. A decrease in BPR indicates underdevelopment of the brain, and an increase indicates dropsy of the brain.

Human chorionic gonadotropin hormone has two fractions: alpha and beta. For the diagnosis of congenital pathology, the determination of the level of beta-hCG is of greatest importance. A decrease in hCG below normal levels is observed with ectopic pregnancy, placental pathology, and Edwards syndrome. An increase in hCG may indicate:

1. Multiple pregnancy;
2. Genetic diseases of the fetus.

Plasma protein PAPP-A is determined from the 8th week of pregnancy. It is noteworthy that the determination of this indicator after the 14th week is no longer so reliable.

A decrease in PAPP-A in comparison with normal values ​​characteristic of a certain stage of pregnancy indicates:

• Chromosomal abnormalities of the fetus;
• Threatened miscarriage.

It is worth noting that an increase in plasma hormone may also indicate the presence of fetal developmental disorders.

Second screening during pregnancy

Screening in the second trimester is primarily carried out to confirm or refute the results of the first screening, as well as if indicated. The second screening is recommended to take place at 16-20 weeks of pregnancy.

Pregnant women undergo the following studies:

• Biochemical examination of the fetus (hCG, AFP, estriol).

Ultrasound of the fetus in the second trimester

The need to conduct an ultrasound in the second trimester is dictated by the fact that during this period important functional systems have already been formed, the study of which will allow us to assess the development of the child. Ultrasound helps to study:

• Correct formation of the spine and limbs;
• Length of the nasal bone;
• Dimensions of brain structures;
• Functioning of internal organs;
• Basic parameters of the child;
• Dimensions and structure of the placenta;
• Cervical dimensions;
• Amniotic fluid level;
• Fetal heart rate;
• Umbilical cord length;
• Condition of the appendages of a pregnant woman.

Examination of the placenta allows the doctor to determine its location. Normally, the placenta is located on the posterior wall of the uterus, approximately 6-8 cm above the internal os. If it is located at the bottom of the uterus and closes the internal os, this is a deviation from the norm.

Alpha fetoprotein (AFP) is a protein synthesized by the fetal liver. The substance enters the mother’s body through the placenta, making it possible to determine its concentration by examining the venous blood of the pregnant woman.

A low ACE level is observed when:

• Down syndrome;
• Edwards syndrome;
• Hydatidiform mole;
• Fetal death.

A high concentration of alpha-fetoprotein may indicate:

• Hernia in the navel;
• Abnormal formation of the fetal neural tube;
• Abnormal formation of the esophagus or duodenum;
• Meckel's syndrome.

What to do if the results are unsatisfactory?

First of all, it is worth noting that screening is a complex study. This means that if one of the results is unsatisfactory, and the rest are normal, this does not indicate the presence of pathology. Moreover, even if the results are collectively unsatisfactory, this does not mean that the child is 100% likely to be born sick. Screening allows you to assess only the degree of likelihood of developing pathology in a particular child.

If the doctor deems it necessary, he will refer the woman to a geneticist. If there is a high risk of congenital pathologies, the pregnant woman is sent for amniocentesis or chorionic villus biopsy. Amniocentesis allows a specialist to detect the presence of congenital and hereditary diseases by examining amniotic fluid.

Chorionic villus biopsy can also identify chromosomal pathologies and genetic diseases.

Remember: The doctor makes a conclusion about the risk of having a baby with a pathology based on the results of all screening studies. If you receive an unsatisfactory result, you should never panic. The doctor will recommend additional tests, the results of which may refute all worries about the child’s health.

Grigorova Valeria, medical observer