A referral for a screening examination causes panic among expectant mothers. A lot of questions arise - what is this, is it dangerous for the baby, why are they sending me? In order not to worry unnecessarily during such a crucial period, it is better to deal with this issue in advance.

What is screening

The Ministry of Health recommends that women expecting a child undergo examinations in the first trimester in order to identify abnormalities in fetal growth in the early stages. Perinatal testing does not seem to pose a threat to the mother and child. The price of the study is affordable, so there is no need to risk the life of the unborn baby. Screening during pregnancy helps to identify:

• genetic pathologies;
• indirect signs of violations;
• fetal malformations.

Everyone who is at risk should be screened during pregnancy in the 1st trimester. These are women who have:

• the father of a child who received radiation;
• age category over 35 years;
• threat of miscarriage;
• hereditary diseases;
• occupational hazard;
• children born with pathologies;
• previous frozen pregnancy, miscarriages;
• family relationship with the child's father;
• drug and alcohol addiction.

First screening during pregnancy

It is important to conduct a screening test for the first time if the price at stake is the life of the unborn baby. What can be revealed during the examination? First trimester screening can detect:

• defects of the central nervous system;
• genetic diseases - Edwards, Down syndromes;
• the presence of an umbilical hernia;
• slow growth of skeletal bones;
• disorders of brain formation;
• increased or slow heartbeat;
• one umbilical artery (there should be two).

What do they look for at the first screening?

An important component of the mother’s calm state and confidence in the correct development of the baby are screenings during pregnancy. Important parameters of the fetus are measured during the first ultrasound examination:

• the size between the parietal tubercles;
• TVP – thickness dimension of the collar space;
• KTR size – from the coccyx to the bone on the crown;
• length of bones - forearm, thigh, lower leg, shoulder;
• heart size;
• Head circumference;
• vessel sizes;
• the distance between the frontal and occipital bones;
• heart rate.

First screening during pregnancy - timing

What determines the time of the first screening test? An important indicator in the fetus is the thickness of the collar space. The period when the first screening is done is the beginning of the 11th week; earlier the TVP value is too small. The end of the period is associated with the formation of the fetal lymphatic system. After 14 weeks, the space fills with fluid and can increase, as in pathology - and the results will not be objective. The end of the period is considered to be 13 weeks plus an additional 6 days.

Preparing for 1st trimester screening

An ultrasound examination does not require preparation if the examination is performed through the vagina. When testing through the abdominal wall, you need to fill the bladder with three glasses of water 1.5 hours before starting. How to prepare for the 1st trimester screening, its second component – ​​a blood test? To obtain an objective result you need:

• two days before, do not eat seafood, nuts, chocolate, smoked and fried foods;
• in the morning on the day of the event, do not drink anything;
• donate blood on an empty stomach.

How to do the first screening during pregnancy

Wanting to exclude defects and determine inconsistencies in fetal development, women in the first trimester are sent for examination. After deciphering the results and comparing them with the standards, a decision is made. If indicators are poor, termination of pregnancy is possible. How is 1st trimester screening performed? The study includes two stages:

• ultrasound examination, during which measurements of the fetus are taken, the characteristics of its vital functions and the condition of the uterus are established;
• biochemical analysis of maternal blood, revealing the absence of chromosomal defects.

First screening during pregnancy - norms

After the study, specialists compare the resulting indicators with the standards. An important point is the dependence of these values ​​on the correct stage of pregnancy: in what exact week the test was carried out. The 1st trimester screening standards for ultrasound results are:

• coccyx-parietal size – 34-75 mm;
• the nasal bone is present, not measured at 11, 12 weeks, then the value exceeds 3 millimeters;
• heart rate – 147-178 beats per minute;
• size between the parietal bones – 13-28 mm;
• The thickness of the collar space is in the zone of 0.8 - 2.7 mm.

Biochemical hemoanalyses have their own standards. They are influenced by the week of the study. After receiving the results, the MoM coefficient is calculated using a computer, showing deviations in fetal development. The parameters are proportional to the period:

• beta-hCG – 14.2-130.9 ng/ml;
• calculated MoM coefficient – ​​0.51-2.5;
• PAPP-A – 046- 8.53 mIU/ml.

Ultrasound screening 1st trimester

The main examination of this period is ultrasound. Based on its results (if there are concerns about chromosomal defects), blood tests are prescribed. Screening ultrasound of the 1st trimester checks the fetus, in addition to measuring parameters:

• structure and symmetry of the brain;
• ductus venosus blood flow;
• the presence of an umbilical hernia;
• position of the stomach, heart;
• number of umbilical cord vessels.

During a screening study, measurements and monitoring of the pregnant woman’s condition are carried out. The indicators will tell you about the threats to fetal development. Increased uterine tone can provoke spontaneous abortion. During an ultrasound examination, a woman is diagnosed with:

• location, thickness of the placenta;
• uterine tone;
• amount of amniotic fluid;
• picture of the cervical pharynx.

Biochemical screening

If abnormalities are detected by ultrasound, blood tests are prescribed to clarify the threat of chromosomal pathologies. The results are interrelated with the timing accurately determined by ultrasound examination. Maternal venous blood serum is taken for analysis. Based on the results, the risk of anomalies is calculated. The hemotest determines 2 parameters that are compared with the standard:

• free hCG beta subunit;
• plasma protein A – PAPP-A.

1st trimester screening - interpretation of results

After the research, specialists use computer processing to transcribe the research. The screening results of the 1st trimester depend on the week in which they are carried out and have different indicators. When performing an ultrasound:

• determine the presence and size of the nasal bone - more than 3 millimeters;
• measure the thickness of the collar space - an increased indicator indicates the likelihood of pathology.

Decoding the results of blood biochemistry is also related to the week in which it is carried out:

• beta-hCG levels are below the standard - the likelihood of an ectopic, frozen pregnancy, miscarriage;
• the results are high - toxicosis, the presence of several fetuses, tumors, Down syndrome are possible;
• PAPP-A values ​​are higher than normal – threat of miscarriage, frozen pregnancy;
• the data is underestimated - Down syndrome, Edwards syndrome, and miscarriage are likely.

Price for 1st trimester screening

Screening studies are carried out in perinatal clinics and medical centers. Some of them have websites where you can order from catalogs and buy in an online store (often at a discount) the required examinations. These include a double pregnancy test and ultrasound. How much does 1st trimester screening cost? The stated price is determined by the level of the institution, equipment, and staff experience. The cost difference in rubles is:

• Ultrasound – 1600-5000;
• double hemotest – 1400-3100.

Video: 12 week screening

Biochemical screening is a test of a pregnant woman's blood to determine specific markers that help determine the likelihood of severe genetic disorders in the fetus.

From the moment of its formation, the placenta begins to produce certain substances, which then penetrate into the maternal blood. The number of these markers normally changes constantly as the fetus develops. The determination of these substances is the basis of biochemical screening: significant deviations of the results obtained from accepted norms indicate a high possibility of the presence of chromosomal abnormalities or.

information Of course, such laboratory tests cannot make a diagnosis, but they help to select a group of women at high risk of having children with pathology and offer them further in-depth examination to clarify the situation.

Biochemical screening is performed twice during the entire period of gestation: in the first trimester (10-14 weeks) and in the second trimester (16-20 weeks).

Indications for use

The need for biochemical screening in all pregnant women is still controversial. Most experts recommend this test for all patients, because no one is immune from genetic disorders. The World Health Organization (WHO) recommends at least mandatory laboratory tests for all pregnant women.

This analysis is not mandatory, and the decision to perform it is voluntary for every expectant mother, although, of course, it won’t hurt to insure yourself once again.

In addition, groups of women who have a high risk of having children with genetic pathology have been identified. Such patients should be examined twice during the entire gestation period.

At-risk groups, requiring mandatory biochemical screening:

• The woman’s age is over 30 years old during the first pregnancy and over 35 years old during the second and subsequent ones;
• 2 or more spontaneous abortions in the anamnesis;
• Self-administration of medications in the early stages that have a teratogenic effect;
• Infectious diseases suffered in the first trimester;
• Presence of relatives in the family with genetic abnormalities;
• The presence of genetic abnormalities in one or both parents;
• Previous birth in the family of a child with genetic abnormalities;
• Stillbirth or death of another child from developmental defects in the family previously;
• Marriage between close relatives;
• Radiation exposure of one or both parents before conception or in early pregnancy;
• Abnormalities detected on fetal ultrasound.

First biochemical screening

Biochemical screening of the 1st trimester is performed at 10-14 weeks, but most experts consider it more informative to conduct a study at 11-13 weeks.

The first screening is a “double test”, i.e. detect two substances in the blood: (in particular, free unit of human chorionic gonadotropin) and PAPP-A (plasma protein A associated with pregnancy).

Norms

Human chorionic gonadotropin is secreted by the cells of the chorion (the membrane of the embryo), so it begins to be detected in the blood quite early (already in the first days after conception has occurred). Then its amount gradually increases, reaches a maximum at the end of the first trimester, then begins to decrease and remains at a constant level from the second half of pregnancy.

Normal hCG levels

RARR-A is a protein produced by the trophoblast throughout the entire gestation period, its amount constantly increases in proportion to the duration of pregnancy.

Normal indicators of PAPP-A

additionally The result of biochemical screening is assessed not only by the results obtained, but also by the MoM value, which ultimately is the determining factor. MoM is a coefficient showing the degree of deviation of the obtained indicator from the average normal indicator for a given period of pregnancy. The normal MoM ranges from 0.5 to 2.5 (for multiple pregnancies, up to 3.5 MoM).

Decoding

Explanation of biochemical screeningshould only be carried out by the attending physician. It should be borne in mind that each laboratory, depending on the reagents used, may have its own standards for indicators; therefore, using incorrect data, you can get false results.

Decoding the analysis for hCG

Decoding the analysis for PAPP-A

Biochemical screening in the second trimester

Biochemical screening of the 2nd trimester consists of a “triple test”: determination of AFP (alpha-fetoprotein), hCG and free estriol. The analysis is performed from 16 to 20 weeks, but the most informative examination will be at 16-18 weeks.

Triple Test Standards

AFP– a protein produced in the gastrointestinal tract and liver of the fetus from the early stages of its development.

Normal AFP values

Normal hCG levels

Free estriol is a hormone produced initially only by the placenta, and then by the child’s liver. During normal pregnancy, the amount of free estriol constantly increases.

Normal levels of free estriol during pregnancy

Decoding

2 biochemical screening should also be deciphered only by the attending physician, taking into account the standards of the given laboratory.

Deciphering the AFP analysis

Explanation of the analysis for free estriol

Many women who are preparing to undergo their first examinations during pregnancy are interested in what the 1st trimester screening standards are.

If you want to know what indicators characterize the fetus at this time, what the result of ultrasound and tests may be, and how to properly prepare to donate blood, then read this article.

First trimester screening is an important undertaking that should not be neglected.

The test results that you will receive after undergoing it will allow doctors to assess the actual condition of your child and make the right conclusions regarding the further course of pregnancy.

Women in the first trimester of pregnancy are often surprised to learn that the first screening of their condition and fetal development is carried out through two procedures: ultrasound diagnostics and blood sampling.

Most often, at this stage, an ultrasound of the fetus is performed abdominally - through the abdominal walls of the mother's abdomen.

A woman who is going to undergo such an ultrasound should prepare for it - drink several glasses of cool, still, clean water.

Fluid entering the bladder will create some stress on the uterus, and an ultrasound will be performed to obtain more accurate data.

The sonologist performing the ultrasound evaluates the development of the child, which should correspond to his gestational age, and the biometry of the fetus, comparing the actual size of the fetus with the normative ones.

After this, the doctor measures various parameters, the analysis of which can give an informative conclusion about the actual condition of the fetus, confirm or exclude the presence of pathologies of its development.

The optimal time for the first pregnancy screening is the twelfth to thirteenth week of its development. The result of the study consists of several factors.

Below you can see the average data, which are normative for children of this gestational age.

The standard thickness of the collar space, measured at this time, should range from one and a half to two and a half millimeters.

If the thickness of the VP is greater, doctors may suspect various chromosomal abnormalities of the fetus. You can clarify their presence by visiting a number of additional prenatal non-invasive diagnostics.

It is important to pay attention to the fact that TVP is measured only at the first pregnancy screening, since it cannot be determined at subsequent ultrasounds.

In addition, the following fetal indicators are analyzed (at the twelfth to thirteenth week of pregnancy):

1. the size of the nasal bone is at least three millimeters;
2. heart rate - from one hundred and fifty to one hundred and seventy beats per minute;
3. blood flow spectrum in the fetal ductus venosus;
4. the size of the baby's upper jaw bone;
5. bladder capacity.

An ultrasound result, signaling possible deviations from the norm, may indicate the presence of various gene abnormalities, in particular Down syndrome.

Fetal biometry carried out at the twelfth to thirteenth gestational week of development must meet the following standard indicators:

• biparietal size - from fourteen to twenty-six millimeters;
• coccygeal-parietal size - from thirty-two to seventy-four millimeters;
• head circumference - from sixty-two to ninety-eight millimeters;
• abdominal circumference - from fifty-one millimeters to seventy-eight millimeters;
• thigh bone length - from five and a half to twelve and a half millimeters;
• the child’s height is from ninety to one hundred and ten millimeters;
• weight - around seventy grams.

HCG norms during the first screening (blood test)

The best time to take a blood test is the day on which you will undergo an ultrasound.

In order for the data to be as accurate as possible, you should prepare for blood sampling - do not eat for twelve hours before the procedure, and also follow a mandatory diet.

Eliminate from your diet:

• chocolate and other sweets;
• meat, fish, smoked meats;
• carbonated drinks.

Doctors who draw blood from pregnant patients send it to a special laboratory.

At this point it is tested for two indicators:

1. human chorionic gonadotropin (hCG);
2. RARR-A.

Ideally, screening for the first trimester of pregnancy should take place within one day. Early in the morning you must donate blood from a vein, then undergo an ultrasound procedure.

Thanks to this, the result of double diagnosis will be accurate and will help doctors reliably determine the condition of the fetus.

Human chorionic gonadotropin is a hormone that is present in the blood of every pregnant woman. Its quantity allows you to determine the exact gestational age of the fetus.

The normal level of human chorionic gonadotropin in the twelfth to thirteenth week of pregnancy is from thirteen and a half to one hundred and fifteen ng/ml.

Elevated levels of hCG may indicate various genetic abnormalities in the development of the child.

However, the level of hubbub, which differs more from the norm, may indicate other factors:

• multiple pregnancy;
• acute toxicosis;
• intoxication with various drugs taken by a woman during the first trimester of pregnancy;
• maternal diabetes mellitus;
• various tumor neoplasms of unknown origin;
• the presence of Down syndrome in the fetus;
• hydatidiform mole.

In turn, a reduced level of human chorionic gonadotropin may indicate:

• for ectopic pregnancy;
• for a frozen pregnancy;
• the presence of a threat of miscarriage;
• for the presence of Edwards syndrome in the fetus.

If the test result causes serious concern to the gynecologist supervising the pregnancy, then most likely he will prescribe an additional invasive procedure, consisting of chorionic villus biopsy.

This procedure will make it more likely to clarify the condition of the fetus and confirm or exclude the presence of anomalies in its development.

PAPP-A norms during the first screening (blood test)

PAPP-A is a protein compound that is produced by the outer layer of the placenta of a pregnant woman.

The presence of this protein is recorded in the blood throughout pregnancy. PAPP-A levels increase with each gestational stage of development of the child in the womb.

If the result of a blood sample tested for the presence and level of PAPP-A worries the doctor, the doctor will prescribe a number of additional prenatal non-invasive diagnostics.

The result of a blood test for the presence of PAPP-A, carried out during the first pregnancy screening, should range from one to eight and a half mU/ml.

A lag in PAPP-A levels from standard values ​​corresponding to the current gestational age of the fetus may indicate the presence of Down or Edwards syndrome.

The result of an analysis that reveals an increased level of PAPP-A may signal a missed pregnancy or a very real threat of miscarriage.

It should be remembered that the best time to donate blood tested for PAPP-A is the twelfth to thirteenth week of pregnancy.

After the fourteenth gestational week, the result of the PAPP-A analysis may lose its information content.

It is best if you go through all stages of first trimester screening at one medical facility.

Computer programs developed to systematize data obtained during examinations, which are used in various medical institutions, have different settings.

Therefore, to maintain the reliability of the data, you should sign up for blood sampling and ultrasound at the same clinic. You can undergo these tests both in a city and in a private hospital.

If the blood biochemistry result that you receive after taking the tests alerts the doctor, despite the fact that the first ultrasound does not cause any complaints, then the doctor will recommend that you undergo additional examination.

At the first stage, it consists of repeated ultrasound diagnostics.

If the result of this procedure is uninformative and cannot clarify the picture, then most likely you will be referred to an ultrasound with Doppler ultrasound.

Combined screening, carried out at the end of the first trimester of pregnancy at the twelfth to thirteenth week of the fetus's gestational age, will assess vital signs and draw conclusions about the health of the child in the womb.

Every woman who cares about the baby’s condition must undergo an ultrasound and donate blood for PAPP-A and human chorionic gonadotropin.

These procedures are absolutely safe and do not cause any harm to either the woman’s condition or the health of the fetus.

Patients are interested in when the first screening is done, and whether there is a time frame that allows them to delay or speed up testing. The timing is determined by the gynecologist leading the pregnancy. It is often prescribed from 10 to 13 weeks after conception. Despite the short duration of pregnancy, tests accurately show the presence of chromosomal disorders in the fetus.

Women at risk must be screened by week 13:

• who have reached 35 years of age;
• under 18 years of age;
• having a family history of genetic diseases;
• those who have previously experienced spontaneous abortion;
• who gave birth to children with genetic disorders;
• sick with an infectious disease after conception;
• having conceived a child from a relative.

Screening is prescribed for women who have had viral diseases in the first trimester. Often, not knowing what her position is, a pregnant woman is treated with conventional medications that negatively affect the development of the embryo.

What should I show?

Thanks to the first screening, the expectant mother and the doctor will know exactly how the baby is developing and whether he is healthy.

Biochemical analysis of the 1st screening during pregnancy has certain indicators:

1. HCG norm– identifies Edwards syndrome when the indicators are below the established values. If they are too high, then the development of Down syndrome is suspected.
2. Plasma protein (PAPP-A), the value of which is below established standards indicates the fetus’s propensity for diseases in the future.

An ultrasound examination should show:

• how the fetus is positioned to eliminate the risk of ectopic pregnancy;
• what kind of pregnancy: multiple or singleton;
• whether the fetal heartbeat corresponds to developmental norms;
• embryo length, head circumference, limb length;
• the presence of external defects and disorders of internal organs;
• thickness of the collar space. With healthy development, this corresponds to 2 cm. If compaction is observed, then pathology is likely;
• condition of the placenta to eliminate the risk of dysfunction.

A comprehensive examination, the results of which are shown by the first screening performed, makes it possible to detect various genetic pathologies. If a serious illness is confirmed that threatens the quality of life and health of the unborn child, then parents are offered to terminate the pregnancy artificially.

To accurately confirm the diagnosis, the woman undergoes a biopsy and puncture of the amniotic membrane to obtain amniotic fluid and examine it in the laboratory. Only after this can we confidently say that the pathology exists, and a final decision can be made about the further course of the pregnancy and the fate of the child.

Preparing and conducting screening

The gynecologist leading the pregnancy tells the woman in detail what preparations should be made for the procedure. He also informs about standard examination standards. All points of interest to her should be discussed without withholding information. There are several mandatory nuances for screening in the first weeks.

1. Hormone tests are done on the same day. It is better to do the first screening in one laboratory. The expectant mother should not worry and understand that donating blood from a vein is extremely necessary for her. Unpleasant sensations when taking the test will quickly pass, the main thing is to get the result.
2. Blood is donated on an empty stomach. You can drink some boiled water if you are very thirsty.
3. Weighing. Before screening, it is advisable to weigh yourself, since weight and height data are important for the procedure.

The test results are received by the doctor or the pregnant woman herself.

Results and standards of the study

Typically, laboratories issue forms that indicate the standard indicators of the norm and the results of the pregnant woman obtained in the laboratory. The expectant mother will be able to understand them without difficulty.

HCG norms at first screening

These indicators are normal and do not indicate the presence of disorders.

Ultrasound diagnostic indicators

Based on the results, it is possible to determine the symmetry of the fetal cerebral hemispheres and track how the internal organs develop. But the main task of the procedure is to identify chromosomal pathologies and eliminate the risk of their development at a later date.

So screening allows you to timely detect:

• chromosomal abnormalities (triploidy, characterized by an additional set of chromosomes);
• defects in the development of the nervous system;
• umbilical hernia;
• possible presence of Down syndrome;
• predisposition to Patau syndrome, manifested by the embryo receiving 3 thirteenth chromosomes instead of two. Most children born with this rare disease have many physical abnormalities and die within the first few years;
• de Lange syndrome, characterized by gene mutations. Such children are severely retarded in mental development and have significant physical defects;
• Edwards syndrome is characterized by the presence of an extra 18th chromosome. Such children are severely retarded physically and mentally, and are more often born premature;
• Lemli-Opitz syndrome, characterized by severe mental and physical retardation.

If an umbilical hernia is detected, internal organs are damaged, and the heart rate is high, Patau syndrome is suspected. If there is no or too small nasal bone, one existing umbilical artery and a low heart rate, the threat of Edwards syndrome is noted.

When the timing of pregnancy is accurately established, but the ultrasound does not determine the nasal bone, and the facial contours are not expressed, this indicates Down syndrome. Only an experienced specialist will decipher the 1st screening, since erroneous results can lead to strong worries for future parents

When should an expectant mother start worrying?

As you know, the human factor is present everywhere, and even in serious laboratories mistakes can happen. Incorrect results shown by biochemistry are confused with genetic defects. That happens:

• in mothers with diabetes;
• in those carrying twins;
• with early or late 1st screening;
• with ectopic pregnancy.

The following factors accompany false results:

• obesity of the expectant mother;
• conception through IVF, while protein A levels will be low;
• experiences and stressful situations that arose on the eve of the test;
• treatment with drugs whose active component is progesterone.

If PAPP-A with a high level makes you wary only when the ultrasound results are unfavorable, then a low protein content indicates such disorders as:

• fetal freezing;
• pathologies of the primary form of the fetal nervous system;
• high probability of spontaneous abortion;
• risk of premature onset of labor;
• Rhesus conflict between mother and baby.

The blood test is 68% correct, and only in combination with ultrasound can one be confident in the diagnosis. If the standards of the first screening do not meet the requirements, it will be possible to dispel fears at the next test. It must be carried out in the second trimester of pregnancy. When the results of the 1st screening are in doubt, you can be examined in another independent laboratory. It is important to repeat the first screening before the 13th week of gestation.

Parents will need to consult a geneticist, who will recommend further testing. When a repeated study shows that the child has a predisposition to Down syndrome, this is indicated by the thickness of the nuchal translucency and analysis for hCG and PAPP-A. If PAPP-A is higher than expected, and all other indicators correspond to the standard, then there is no need to worry. In medicine, there are cases where, despite the poor prognosis of the 1st and even 2nd screening, healthy children were born.

Let's continue the topic:

Video on the topic

Modern methods of examination during pregnancy stipulate that the expectant mother should three times pass - once in each trimester. And although the term itself is a little scary with its unusual “frightening” medical name, there is nothing alarming or unusual about it. Screening is just a general comprehensive examination of the pregnant woman and the fetus in order to determine various indicators and identify possible abnormalities.

Preparing for screening

Carrying out the first screening during pregnancy requires careful preparation and compliance with a number of requirements and recommendations. During subsequent examinations and trimesters, the list of preparatory activities will become significantly smaller.

Before undergoing the first prenatal screening, a woman should do the following:

• during the day before the examination, refrain from consuming potential products (citrus fruits, seafood, etc.);
• refrain from fried and fatty foods;
• on the morning before the examination, refrain from breakfast until blood is taken for analysis;
• in preparation for abdominal passage (through the stomach), fill the bladder with liquid by drinking 0.5 liters of still water half an hour before the examination.

information In addition, it is advisable to perform normal hygiene procedures, while excluding the use of scented cosmetics or hygiene products.

Standard values

When passing the first screening, special pay attention on following indicators And their compliance recommended standard values.