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What is examined at the first screening. Transcript of the first ultrasound screening. Decoding the analysis for hCG

Expectant mothers have to take many tests and undergo regular examinations by doctors. Among the large number of examinations, it is easy to get confused and many women do not know why this or that analysis is performed. In most cases, the expectant mother really shouldn’t worry too much, but it’s still necessary to know the purpose of screenings and tests. Blood is taken for screening several times during pregnancy.

The first basic test is carried out at the beginning of pregnancy and is known as the 12 week screening. This type of medical examination can be performed from 10 to 13 weeks of pregnancy. It is advisable to undergo an examination before pregnancy to assess the health of the expectant mother. However, as practice shows, most often the first examination is carried out when the patient is registered. The first screening must be done in case of a high risk of pathology formation.

Also, any woman has the right to undergo any tests she wishes:

  • First pregnancy over 35 years of age.
  • The presence of diseases that are inherited and genetic abnormalities.
  • Marriage between close relatives.
  • The analysis is carried out if there have previously been cases of miscarriage, frozen pregnancy or other disorders.
  • Taking potent medications that are not recommended for expectant mothers during pregnancy.
  • Taking alcohol, drugs and illegal drugs.
  • Working with hazardous working conditions.
  • Detection of genetic and other abnormalities in children born to a woman earlier.
  • History of severe inflammation and viral diseases in the early stages of pregnancy.

The patient's venous blood is used for screening. If necessary or at the request of the patient, the standard set of parameters for analysis can be expanded. Biochemical research can include more than 20 basic parameters. In the absence of clear medical indications, additional tests may be chargeable. Private clinics and laboratories charge for a standard examination, and each additional parameter costs an additional fee. It is better to discuss the need for research with your doctor.

Diagnostics

Every woman expecting a child has the right to decide independently whether she needs to undergo screening. From a legal point of view, this type of examination is recommended by doctors, but the expectant mother has the right to refuse tests.

However, this is an unwise approach; from the point of view of the health of the mother and baby, it is better to find out about any possible deviations or disorders as early as possible.

The results of 1 screening provide doctors with a lot of useful information about the health and development of the unborn baby. As a rule, a standard set of studied parameters is used, which makes it possible to detect the following deviations:

  • Risk of developing pathological changes in the fetus
  • Down syndrome
  • Patau syndrome
  • Disturbances in the development and pathology of the neural tube of the fetus
  • Abnormal set of chromosomes
  • Physiological defects of the internal organs of the developing fetus

A screening test does not make it possible to establish a diagnosis or determine with certainty whether the child will be sick. Based on the results of the analysis, one can judge the degree of risk for the development of a particular deviation. Women who are at risk may be offered additional examination. Using an invasive test, amniotic fluid is taken for analysis.

Preparing for analysis

Proper blood sampling and preparation for it ensure the reliability of the results obtained. Blood for research is taken from a vein, but usually the collection of material is completely painless. The procedure is performed in a doctor's office or laboratory. Some private medical institutions can collect material at home for an additional fee:

  • The main question that causes a lot of controversy: are tests performed on an empty stomach or not? You should donate blood strictly on an empty stomach, even if the feeling of hunger is very strong, you cannot eat, you can only drink clean water. You can have breakfast immediately after blood sampling, so many pregnant women take sandwiches or other snacks with them so as not to be hungry.
  • On the eve of the test, it is not recommended to eat chocolate, fatty meat and seafood.
  • When women donate blood, a calm atmosphere is needed. Anxiety, fear, and fast walking to the doctor's office can trigger the activity of certain chemicals and enzymes inside the body.
  • 2-3 days before the test, doctors recommend excluding intimacy.

Test parameters

The blood test is performed in a laboratory setting. When a blood sample is given, a test is performed and the patient or her doctor receives a form with the results. Any questions should be consulted with a physician. One measure is called beta human chorionic gonadotropin, or beta-hCG. This is a hormonal substance that is responsible for the normal development of the fetus in the earliest stages. At first the indicator increases significantly, then gradually decreases.

Standards have been established for β-hCG at various stages of pregnancy for screening:

  • Week 10: 25.8–181.6 ng/ml
  • Week 11: 17.4–130.3 ng/ml
  • Week 12: 13.4–128.5 ng/ml
  • Week 13: 14.2–114.8 ng/ml

It is important that the β-hCG level is within the established norms. High levels of the hormone may indicate the development of Down syndrome in the fetus. This indicator also increases with multiple pregnancies, early manifestations of toxicosis and established diabetes mellitus in the expectant mother. Low β-hCG levels may indicate the development of Edwards syndrome, placental insufficiency, or be a sign of an ectopic pregnancy.

When hormone levels are low, the risk of miscarriage is very high.

The second main indicator is protein A or PAPP-A. This substance is protein in nature and is responsible for the normal development and functioning of the placenta. Exceeding the norm of this indicator is not considered a violation of the body’s functioning. A decrease in the concentration of PAPP-A leads to the threat of miscarriage and may be a sign of the development of Down syndrome, Cornelia de Lange and other pathologies:

  • Week 10-11: 0.45–3.73 mIU/ml
  • Week 11-12: 0.78–4.77 mIU/ml
  • Week 12-13: 1.03–6.02 mIU/ml
  • Week 13-14: 1.47–8.55 mIU/ml

Based on the data obtained, the laboratory calculates another parameter: MoM - coefficient. This value shows the deviation of the values ​​​​obtained as a result of the patient's blood test in comparison with the average values ​​​​established as the norm. For a healthy woman and a normally developing fetus, MoM should be in the range of 0.5-2.5. During multiple pregnancy, the rate increases to 3.5.

Reliability of analyzes and risks

Interpretation of blood test results for screening should only be carried out by a qualified physician who is familiar with the patient’s medical history. It should also be taken into account that screening for twins will show a completely different result. The second child increases the levels of certain chemicals in the mother's body. Every doctor has information with recommended standards for the parameters under study.

However, the individual characteristics of the body and the composition of the patient’s blood before pregnancy should be taken into account.

With the screening analysis and the correctness of the research at all stages, the reliability of the result is estimated at 95%. However, the analysis cannot accurately determine whether the fetus will have a pathology or not. The degree of risk is assessed.

The results contain numerical designations and verbal expression:

  • “Low”/1:10000 (and below this mark), this means there is a low degree of risk for the development of any pathological conditions of the fetus.
  • “Medium”/1:1000 means that there is an average degree of risk, additional examination may be required.
  • “High”/1:380 means that there is a high probability that the fetus will have developmental disorders. Additional tests are recommended.
  • “Extremely high”/1:100 means that the woman needs additional examinations and consultation with a genetic specialist. In some cases, the doctor may recommend termination of the pregnancy.

After receiving the results, a good or bad prognosis is possible. Based on the results of the first prenatal examination, some types of pathologies can be excluded. What to do if the screening is bad? First of all, don't worry, stress can harm you much more than the possible risks. You will have to decide how prepared future parents are for the birth of a child with special needs.

Triple test

Blood is donated at the second screening at 20-25 weeks of pregnancy. You should take the test, just like the first one, on an empty stomach. After the woman has done the analysis, a consultation with a doctor is held. The second test includes an analysis of those key indicators: hCG, alpha-fetoprotein and free estyrol.

The reliability of the second screening is lower compared to the first.

In medicine, it is generally accepted that this type of research is 80% effective. However, the reliability of the “2nd screening” test is only possible if the exact date of conception is known. Otherwise, the reliability of the results obtained drops to 20%, since the standards for hormones and chemicals change with each week of pregnancy.

For blood, screening is carried out several times, at the same time it is necessary to do an ultrasound examination. Modern diagnostic and research methods of medicine make it possible to identify pathological and genetic changes in the heart in the early stages of pregnancy. If necessary, consultation with specialists and treatment are carried out.

In contact with

With the onset of pregnancy, a woman begins to worry about many questions. Every expectant mother wishes her baby normal formation and development. In the early stages, there may be risks of developing certain diseases of the embryo. To study the baby’s condition, doctors prescribe 1st trimester screening. A woman can find out the norms for ultrasound (a photo of the examination performed is usually attached) from the specialist who is observing her.

What is perinatal screening?

Perinatal screening involves examining a pregnant woman to identify various defects of the child at the stage of intrauterine development. This method includes two types of examination: a biochemical blood test and an ultrasound examination.

The optimal period for conducting such an examination has been determined - a period from ten weeks and six days to thirteen weeks and six days. There is a certain standard for ultrasound screening in the 1st trimester, with which the results of the examination of a pregnant woman are compared. The main task of ultrasound at this time is to identify serious and identify markers of chromosomal abnormalities.

The main anomalies are:

  • TVP size - the thickness of the space of the collar zone;
  • underdevelopment or absence of nasal bones.

Ultrasound during pregnancy can reveal signs of a disease such as Down syndrome, and some other pathologies of fetal development. The screening norm (ultrasound) of the 1st trimester should be analyzed before 14 weeks. After this period, many indicators are no longer informative.

1st trimester screening: ultrasound norms (table)

To make it easier for a doctor to determine the condition of a pregnant woman, there are certain tables of indicators of the development of the baby’s organs. The ultrasound examination protocol itself is drawn up in a structured manner so that the dynamics of the formation and growth of the embryo are clear. The article presents screening standards for the 1st trimester.

An ultrasound transcript (the table below) will help you get information about whether everything is okay with the fetus.

Determination of embryo viability

To assess the viability of the embryo, it is very important to look at the heartbeat in the early stages. A small person’s heart begins to beat already in the fifth week of being in the mother’s womb, and it can be detected using 1st trimester screening (ultrasound standards) as early as seven weeks of the fetus’s life. If at this time a heartbeat is not detected, we can talk about the likelihood (frozen pregnancy).

To assess the viability of the embryo, the heart rate is also taken into account, which normally ranges from 90 to one hundred and ten beats per minute at a period of six weeks. These important indicators of 1st trimester screening, ultrasound standards, together with the study of blood flow and body length, must correspond to the reference data for the duration of pregnancy.

The more modern equipment is used for examination, the better you can see all organs and get the most accurate results. If there is a high probability of congenital defects or genetic developmental abnormalities, then the pregnant woman is sent for a more in-depth examination.

In some regions, when registering with antenatal clinics, 1st trimester screening is mandatory for all pregnant women. Ultrasound standards may not coincide with the results obtained, so doctors immediately take the necessary measures to preserve the life and health of the child or mother. But most often, pregnant women who are at risk are referred for such an examination: these are women from thirty-five years of age, those who have genetic diseases in their family and previously born children, had miscarriages in previous pregnancies, stillborn children or non-developing pregnancies. Close attention is also paid to expectant mothers who suffered viral diseases at the beginning of pregnancy, are taking dangerous medications or are under the influence of radiation.

If a woman has spotting in the first trimester, then an ultrasound makes it possible to determine the degree of viability of the child or its death.

Dates of pregnancy

An additional examination to determine the exact date of pregnancy is indicated for women who have an irregular menstrual cycle or do not even know approximately the date of conception of the child. For this, in most cases, 1st trimester screening is used. Ultrasound standards, deciphering the main indicators and dates of conception do not require special medical knowledge. The woman herself can see the expected date of birth, gestational age and number of embryos. Basically, the number of weeks determined by ultrasound corresponds to the period that is calculated from the first day of the female cycle.

While conducting the study, the doctor takes control measurements of the size of the embryo. The specialist compares the 1st trimester screening standards with the data obtained. Ultrasound interpretation occurs according to the following parameters:

  • measuring the distance between the sacrum and the crown of the embryo (7-13 weeks), making it possible to determine the real gestational age using special tables;
  • measuring the length of the head of the unborn child (after 13 weeks), this is an important indicator in the second half of pregnancy;
  • determining the size of the longest - the femur of the embryo's body, its indicators reflect the child's growth in length (at 14 weeks), in the early stages it should be approximately 1.5 cm, and by the end of bearing the child it will increase to 7.8 cm;
  • measuring the abdominal circumference of a child - indicates the size of the embryo and its estimated weight;
  • determination of the head circumference of a maturing fetus, which is also used to predict the natural birth of a child. This measurement is carried out in the last stages of pregnancy, according to which the doctor looks at the size of the small pelvis of the expectant mother and the child’s head. If the head circumference exceeds the parameters of the pelvis, then this is a direct indication for a cesarean section.

Definition of malformations

Using ultrasound in the first weeks of pregnancy, various problems in the development of the child are identified and the possibility of treating it before birth. For this purpose, an additional consultation with a geneticist is scheduled, who compares the indicators obtained during the examination and the screening norms of the 1st trimester.

An ultrasound scan may indicate the presence of any malformations in the child, but the final conclusion is given only after a biochemical study.

1st trimester screening, ultrasound norms: nasal bone

In an embryo with chromosomal abnormalities, ossification occurs later than in a healthy one. This can be seen as early as 11 weeks, when the 1st trimester screening is carried out. Ultrasound standards, the interpretation of which will show whether there are deviations in the development of the nasal bone, help the specialist determine its size starting from 12 weeks.

If the length of this bone does not correspond to the gestational age, but all other indicators are in order, then there is no reason to worry. Most likely, these are the individual characteristics of the embryo.

The meaning of the coccygeal-parietal size

An important indicator of the development of a little person at this stage of pregnancy is the size from the tailbone to the crown. If a woman had irregular menstruation, the gestational age is determined by this indicator. The ultrasound screening norm for the 1st trimester of this indicator is from 3.3 to 7.3 cm for a period of ten to twelve weeks inclusive.

Thickness of the collar zone space (TVS)

This indicator is also called the thickness of the neck fold. It has been noted that if the embryonic TVL is thicker than 3 mm, then there is a risk of Down syndrome in the child. The values ​​used by the doctor are shown by 1st trimester screening. Ultrasound standards (nuchal translucency thickness) are considered very important for further monitoring of a pregnant woman.

Determining the location of the placenta

The baby's place (placenta) is necessary for the intrauterine blood supply of a small person. It is needed to provide him with food. Ultrasound makes it possible to determine abnormalities in the development and position of the placenta. If it is located too low relative to the fundus of the uterus, this is called placenta previa, which can lead to blocking the exit for the baby during labor.

A 1st trimester screening ultrasound can show the location of the baby's place well. The norms of such research reject low placenta previa. But even if it is located close to the fundus of the uterus, doctors are in no hurry to sound the alarm, since it may rise as pregnancy progresses. But if the position of the placenta has not changed in the later stages, then the following problems are possible:

  • the placenta can obscure the cervix and prevent natural childbirth;
  • Since the lower part of the uterus is stretched, the placenta can detach from it and cause severe bleeding (placental abruption).

Yolk sac examination

On the 15-16th day of pregnancy from the day of conception, the process of formation begins. This “temporary organ” of the baby is examined by doing an ultrasound (1st trimester screening). The deadlines and standards must show its presence and size. If it has an irregular shape, is enlarged or reduced, then the fetus may have frozen.

The yolk sac is an appendage that is located on the ventral side of the embryo. It contains a supply of yolk necessary for the normal development of the baby. Therefore, checking what the norm for 1st trimester ultrasound screening is in comparison with the study parameters is very important for monitoring the progress of pregnancy. Indeed, at first (until the child’s organs function independently), this appendage performs the function of the liver, spleen, and is also used as a supplier of primary germ cells that are actively involved in the formation of immunity and metabolic processes.

The role of biochemical blood test

When examining the condition of the embryo, the doctor looks not only at the results of ultrasound (1st trimester screening). The norms in it are just as important as in a blood test. Such an analysis, in addition to an ultrasound examination, is carried out to determine at what level specific proteins (placental) are located. The first screening is done in the form of a double test - to detect the level of 2 protein types:

  1. "PAPP-A" - the so-called pregnancy-associated plasma protein A.
  2. "HCG" - free

If the levels of these proteins are altered, this indicates the possible presence of various chromosomal and non-chromosomal disorders. But identifying an increased risk does not mean that there is definitely something wrong with the embryo. Such results of screening of the 1st trimester, interpretation, ultrasound normal indicate that it is necessary to more closely monitor the progress of pregnancy. Often repeated testing no longer shows the risk of genetic diseases.

Screening examinations help identify the risk of chromosomal diseases in a child before birth. In the first trimester of pregnancy, an ultrasound and biochemical blood test for hCG and PAPP-A are performed. Changes in these indicators may indicate an increased risk of Down syndrome in the unborn child. Let's see what the results of these tests mean.

For what period?

Screening of the 1st trimester is done for a period of up to 6 days (the period is calculated from the first day of the last menstruation).

Signs of Down syndrome on ultrasound

The coccygeal-parietal size (CPR) must be at least 45 mm.

If the position of the baby in the uterus does not allow you to adequately assess TVP, then the doctor will ask you to move, cough, or lightly tap on the stomach so that the baby changes position. Or the doctor may advise you to come for an ultrasound a little later.

The measurement of TVP can be carried out using ultrasound through the skin of the abdomen, or through the vagina (this depends on the position of the child).

Although the thickness of the nuchal translucency is the most important parameter in assessing the risk of Down syndrome, the doctor also takes into account other possible signs of abnormalities in the fetus:

    The nasal bone is normally detected in a healthy fetus after pregnancy, but is absent in approximately 60-70% of cases if the child has Down syndrome. However, in 2% of healthy children, the nasal bone may not be detected on ultrasound.

    The blood flow in the ductus venosus (Arantius) should have a certain appearance, which is considered normal. In 80% of children with Down syndrome, blood flow in the Arancia duct is impaired. However, 5% of healthy children may also exhibit such abnormalities.

    Reduced maxillary bone size may indicate an increased risk of Down syndrome.

    An increase in bladder size occurs in children with Down syndrome. If the bladder is not visible on an ultrasound scan, then this is not scary (this happens in 20% of pregnant women at this stage). But if the bladder is not noticeable, then the doctor may advise you to return for a repeat ultrasound in a week. At term, in all healthy fetuses, the bladder becomes noticeable.

    A rapid heartbeat (tachycardia) in the fetus may also indicate an increased risk of Down syndrome.

    The presence of only one umbilical artery (instead of two normally) increases the risk of not only Down syndrome, but also other chromosomal diseases (etc.)

Norm of hCG and free β-hCG subunit (β-hCG)

HCG and free β (beta) subunit of hCG are two different indicators, each of which can be used as a screen for Down syndrome and other diseases. Measuring the free β-subunit of hCG can more accurately determine the risk of Down syndrome in an unborn child than measuring total hCG.

The norms for hCG depending on the length of pregnancy in weeks are possible.

Norms for the free β-subunit of hCG in the first trimester:

    9 weeks: 23.6 – 193.1 ng/ml, or 0.5 – 2 MoM

    10 weeks: 25.8 – 181.6 ng/ml, or 0.5 – 2 MoM

    11 weeks: 17.4 – 130.4 ng/ml, or 0.5 – 2 MoM

    12 weeks: 13.4 – 128.5 ng/ml, or 0.5 – 2 MoM

    13 weeks: 14.2 – 114.7 ng/ml, or 0.5 – 2 MoM

Attention! Norms in ng/ml may vary between laboratories, so the data provided is not final, and you should always consult your doctor. If the result is indicated in the MoM, then the standards are the same for all laboratories and for all analyses: from 0.5 to 2 MoM.

What if the HCG is not normal?

If the free β-subunit of hCG is higher than normal for your gestational age, or exceeds 2 MoM, then the baby is at increased risk.

If the free β-subunit of hCG is below normal for your stage of pregnancy, or less than 0.5 MoM, then the baby is at increased risk.

Norm PAPP-A

PAPP-A, or “pregnancy-associated plasma protein A” as it is called, is the second indicator used in the biochemical screening of the first trimester. The level of this protein constantly increases during pregnancy, and deviations in the level may indicate various diseases in the unborn child.

The norm for PAPP-A depending on the stage of pregnancy:

    8-9 weeks: 0.17 – 1.54 mU/ml, or from 0.5 to 2 MoM

    9-10 weeks: 0.32 – 2.42 mU/ml, or from 0.5 to 2 MoM

    10-11 weeks: 0.46 – 3.73 mU/ml, or from 0.5 to 2 MoM

    11-12 weeks: 0.79 – 4.76 mU/ml, or from 0.5 to 2 MoM

    12-13 weeks: 1.03 – 6.01 mU/ml, or from 0.5 to 2 MoM

    13-14 weeks: 1.47 – 8.54 mU/ml, or from 0.5 to 2 MoM

Attention! The norms in mIU/ml may vary between laboratories, so the data provided is not final, and you should always consult your doctor. If the result is indicated in the MoM, then the standards are the same for all laboratories and for all analyses: from 0.5 to 2 MoM.

What if PAPP-A is abnormal?

If PAPP-A is below normal for your gestational age, or is less than 0.5 MoM, then the baby has an increased risk of and.

If PAPP-A is higher than normal for your gestational age, or exceeds 2 MoM, but other screening indicators are normal, then there is no cause for concern. Studies have shown that in the group of women with elevated levels of PAPP-A during pregnancy, the risk of diseases in the fetus or pregnancy complications is no higher than in other women with normal PAPP-A.

What is risk and how is it calculated?

As you may have already noticed, each of the biochemical screening indicators (hCG and PAPP-A) can be measured in MoM. MoM is a special value that shows how much the obtained analysis result differs from the average result for a given stage of pregnancy.

But still, hCG and PAPP-A are affected not only by the duration of pregnancy, but also by your age, weight, whether you smoke, what diseases you have, and some other factors. That is why, in order to obtain more accurate screening results, all of its data are entered into a computer program that calculates the risk of diseases in a child individually for you, taking into account all your characteristics.

Important: to correctly calculate the risk, it is necessary that all tests are taken in the same laboratory in which the risk is calculated. The risk calculation program is configured for specific parameters, individual for each laboratory. Therefore, if you want to double-check your screening results in another laboratory, you will need to take all the tests again.

The program gives the result in the form of a fraction, for example: 1:10, 1:250, 1:1000 and the like. The fraction should be understood as follows:

For example, the risk is 1:300. This means that out of 300 pregnancies with indicators like yours, one child will be born with Down syndrome and 299 healthy children.

Depending on the resulting fraction, the laboratory issues one of the following conclusions:

    The test is positive – there is a high risk of Down syndrome in the child. This means that you need a more thorough examination to clarify the diagnosis. You may be recommended or.

    The test is negative – the child has a low risk of Down syndrome. You will need to undergo, but additional examinations are not needed.

What should I do if I am at high risk?

If, as a result of screening, you have been found to have a high risk of having a child with Down syndrome, then this is not a reason to panic, much less terminate the pregnancy. You will be referred for a consultation with a geneticist, who will once again look at the results of all examinations and, if necessary, recommend undergoing examinations: chorionic villus sampling or amniocentesis.

How to confirm or refute screening results?

If you think that the screening was carried out incorrectly for you, then you can repeat the examination in another clinic, but for this you will need to retake all the tests and undergo an ultrasound. This will be possible only if the gestational age at this moment does not exceed 6 days.

The doctor says I need to have an abortion. What to do?

Unfortunately, there are situations when a doctor persistently recommends or even forces an abortion based on screening results. Remember: no doctor has the right to do such actions. Screening is not a definitive method for diagnosing Down syndrome and, based solely on poor results, there is no need to terminate the pregnancy.

Tell them that you want to consult with a geneticist and undergo diagnostic procedures to identify Down syndrome (or another disease): chorionic villus sampling (if your pregnancy is -) or amniocentesis (if your pregnancy is -).

The new word “screening” appears in a woman’s vocabulary already in the first trimester of pregnancy. These are tests that show any hormonal imbalances during pregnancy.

Screening is carried out to identify risk groups for development, such as Down syndrome, neural tube defects and Edwards syndrome. The result can be found out after analyzing blood taken from a vein and ultrasound readings. The individual characteristics of the pregnant woman and the development of the unborn child are also taken into account. Everything is taken into account - height, weight, bad habits, use of hormonal drugs.

First trimester screening is a comprehensive examination between 11 and 13 weeks of pregnancy. He must determine the risk of having a child with congenital malformations. Screening includes two tests - an examination and a blood test from a vein.

The first ultrasound determines the baby’s physique, the correct position of the legs and arms. The doctor examines the fetal circulatory system, heart function, and body length relative to normal. In addition, special measurements are made, such as measuring the thickness of the neck fold.

It should be borne in mind that screening in the first trimester is called comprehensive, so it is not worth drawing any conclusions based on just one indicator. If there are suspicions of genetic malformations, the woman is referred for additional research. First trimester screening is optional for all pregnant women. Moreover, in antenatal clinics they mostly don’t do this and you have to donate blood in private clinics. However, those women whose risk of pathologies is increased are still referred for screening. These are those who give birth after 35 years of age, who have family members with genetic pathologies, expectant mothers who have previously had miscarriages or children with genetic disorders.

In the first trimester of pregnancy, a blood test determines the content of b-hCG and PAPP-A, a plasma protein that is associated with pregnancy.

For (16-18 weeks), blood is donated for three hormones - b-hCG, AFP and free estriol, sometimes, as an option, a fourth indicator is added - inhibin A.

Let's figure out a little about what these hormones are and how they can affect the outcome of pregnancy.

HCG is found in maternal serum. This is one of the main hormones during pregnancy. Screening determines. If it is low, then this indicates a pathology of the placenta. Increased levels of the hormone most often occur due to chromosomal abnormalities in the fetus or indicate that you are carrying two or more babies.

The PAPP-A test is a determination of the protein A produced in the blood. Screening also determines the level of this protein. If it is significantly underestimated, then this indicates some chromosomal abnormalities, which in turn can lead to the fact that the baby may develop Down syndrome or Edwards syndrome.

The level of estriol, a female steroid hormone, in maternal blood is measured using screening in the second trimester of pregnancy. Estriol is produced by the placenta during pregnancy. And if it is not produced enough, this indicates possible disturbances in the development of the fetus.

Alpha fetoprotein (AFP) is found in maternal serum. This is also a specific protein that is produced only during pregnancy. If the normal state of the fetus is disrupted, this also affects the results - blood levels decrease or increase. An increase indicates the development of congenital defects and diseases, a decrease indicates Down syndrome. A sharp increase in the amount of AFP can lead to fetal death.

Having the screening results in hand, do not panic if one of the results does not correspond to the norm. It is important to understand that doctors make conclusions based on general conclusions and a comprehensive assessment. In addition, even if a high risk of defects in the fetus is identified, then you need to consult a geneticist.

It is necessary to pay attention to the fact that screening only indicates the possibility that there is a problem; in addition, deviations from the norm can be associated with various reasons - taking hormonal drugs during pregnancy or late tests.

Especially for- Maryana Surma

From Guest

Girls, I’m writing a review in the hope that someone will need my experience. First pregnancy, 33 years old. The pregnancy is very long-awaited. Seeing 2 stripes, happiness knew no bounds. All the joyful moments ended after 1 screening. Ultrasound is excellent, nuchal translucency is normal. I take a blood test - the result is 1:84. The doctor suggests not to worry and take the 2nd trimester screening (huge mistake! Wasted time and didn’t get the final result). The result of the second screening: excellent ultrasound and blood risk 1:40. Next I do a DNA test, the result from Hong Kong is not encouraging. The probability of Down syndrome is 1:20, 99%. But the DNA test result is not a diagnosis and does not serve as a basis for terminating the pregnancy, and the pregnancy is already 19 weeks old. Then the geneticist insists on amniocentesis, convincing that the result may be different. I've been waiting for the amnio result for 3 weeks. During this time I go for an ultrasound again. The results are perfect! Nose, limbs, brain, bones, etc. - Everything is okay! I pray 24 hours a day for health, I cry, I wait, I hope. Then I go for the result of amniocentesis and receive a verdict - a child with Down syndrome! Naturally, I make the decision to interrupt, since I myself worked in a rehabilitation center with such children and I know that the severity of pathologies is not predictable! From a mild form to an immovable log with a bunch of additional complications on the heart and other organs. Now I am in the hospital and waiting for an artificial birth tomorrow. Girls, to summarize, I want to say that if you do not plan to give birth with any diagnosis, do not waste time on unnecessary diagnostics. An ultrasound will not show everything, even with the latest equipment and an experienced doctor. The second screening definitely took me 3 weeks in vain. Now I’m lying and crying, and I’m already 23 weeks pregnant!

Every pregnant woman at a certain stage of bearing a baby is faced with the concept of screening. What it is? Screening means a comprehensive examination that gives an idea of ​​the health and development of the fetus, and also allows you to determine the likelihood of having a child with congenital malformations. Such examinations are carried out every trimester; accordingly, three trimesters of pregnancy involve three screenings.

The first screening during pregnancy makes it possible to identify among expectant mothers those who are at risk for having a child with chromosomal abnormalities and hereditary diseases. Every pregnant woman should familiarize herself with the information: what is included in 1st trimester screening, at what stage it is usually carried out, what are the 1st trimester screening standards and what to do if the examinations show poor results.

Timing and indications for the first screening

First trimester screening can be considered reliable if it is performed between the 11th and 14th weeks. It would be optimal to do screening at 12 weeks of pregnancy. It is for this reason that it is very important to register for pregnancy before this period. The best moment to perform screening in the 1st trimester should be determined by the gynecologist who is caring for the woman’s pregnancy. It is not too late to do screening at 13 weeks of pregnancy, but its results will still be less reliable. It is also worth noting that perinatal screening performed in the first trimester of pregnancy will be more informative than screening in the second trimester.

1 screening during pregnancy is not a mandatory measure, but medical professionals advise not to neglect this examination if a woman wants to be well informed about the health status of her unborn child. There are certain risk groups among pregnant women. If a woman belongs to one of these groups, then the doctor will strongly recommend undergoing 1st trimester screening:

  • the pregnant woman had two or more spontaneous abortions (premature birth);
  • the woman experienced a frozen pregnancy or stillbirth;
  • during pregnancy, the expectant mother suffered a viral or bacterial disease;
  • among family members there are people with genetic pathologies;
  • the woman already has a child with chromosomal abnormalities or severe genetic diseases;
  • the woman was treated with drugs that are prohibited for pregnant women;
  • woman's age is over 35 years;
  • the child's father is a blood relative of the pregnant woman.

The first pregnancy screening is quite informative in terms of identifying the following pathologies:

  • abnormalities of the neural tube (the rudiment of the central nervous system);
  • Smith-Opitz syndrome;
  • Cornelia de Lange syndrome;
  • omphalocele (umbilical cord hernia, manifested by the fact that some internal organs of the fetus are not in the abdominal cavity, but in the hernial sac extending over the skin).

Each pregnancy is individual, which means that screening can proceed differently for different women. For some, it will be enough to undergo the necessary tests once and no longer worry throughout the entire pregnancy. Others are prescribed the same examinations several times. It is worth noting that negative results are not yet a reason to panic. They should be taken as a signal that more careful monitoring of the progress of pregnancy is required.

How is first trimester screening performed? This examination includes an ultrasound examination of the fetus and a biochemical blood test of the mother.

Ultrasound of the first trimester

Ultrasound has long become a universal method with which all pregnant women are examined. The technique is simple to perform, informative and does not pose a threat to the health of the mother and fetus. Over a long period of using the procedure, experts have not found any harm from the effects of ultrasound on fetal development. In obstetrics, two types of ultrasound are used for the 12th week of pregnancy:

  • Transvaginal (a specialist inserts an ultrasound sensor into the vagina);
  • Abdominal (to obtain an image, the sensor is moved across the mother’s abdomen).

How to prepare for an ultrasound? No special preparation is required for an ultrasound examination at 12 weeks of pregnancy. It would be advisable for a pregnant woman to drink about 500-1000 ml of still water, since the amount of amniotic fluid during this period of pregnancy is still insignificant, and it is the amniotic fluid that makes it possible to see the fetus as well as possible. Also, a day or two before the examination, it is better to exclude foods that can increase the formation of gases in the intestines. Excess gases can distort diagnostic results.

Until 10 - 11 weeks of pregnancy, the fertilized egg is extremely small in size - from 2 to 4 mm. The maximum that an ultrasound scan can reveal in the early stages is:

  • location of the embryo;
  • fetal umbilical cord;
  • record the presence of rudiments of the upper and lower limbs;
  • determine the presence of auricular inclinations;
  • determine the condition of a woman’s uterus.

After 10–11 weeks, the fetus reaches the size necessary for a more detailed diagnosis of intrauterine development. This stage of the formation of internal organs and systems of the embryo allows specialists to detect certain developmental defects. Some of these pathologies may even be incompatible with life, therefore, avoiding an ultrasound scan at this time would be quite imprudent.

The main goals that the ultrasound of the first trimester sets for itself:

  • determining the number of fetuses in the uterus;
  • detection of placenta attachment site;
  • identification of abnormal conditions of the fetus;
  • definition of non-developing pregnancy;
  • identifying the threat of spontaneous miscarriage;
  • detection of ectopic pregnancy;
  • detection of pathologies in the reproductive organs of a pregnant woman;
  • assess the quantity and quality of amniotic fluid;
  • determine the occurrence of tumors and cysts.

Diagnosing a number of diseases during the first ultrasound screening gives doctors the opportunity to provide timely assistance to the expectant mother and child in order to avoid complications during pregnancy.

What do specialists first pay attention to when they do an ultrasound scan - screening of the 1st trimester?

First, the doctor will measure the fetal coccygeal-parietal size (CPS). This indicator refers to the size of the fetus from the tailbone to the crown, not taking into account the length of the legs. The CTE value should correspond to the gestational age. A situation in which the fetus is larger than the norm indicates that the baby is developing rapidly and, most likely, the expectant mother will have to bear and give birth to a large child.

A small size of the CTE may indicate either an incorrect timing or the following developmental deviations:

  • genetic abnormalities in the fetus;
  • developmental delay due to hormonal deficiency, infections or other diseases of the pregnant woman;

If the doctor is unable to listen to the heartbeats of the embryo, then intrauterine fetal death is determined. Usually it is accompanied by the disappearance of symptoms of toxicosis. As a result, some expectant mothers worry and wonder why they don’t have toxicosis in the first trimester? However, the absence of nausea and a cheerful state of health at the beginning of pregnancy, although uncommon, is absolutely normal. The first ultrasound will help such women calm down and understand that everything is fine with the baby.

During an ultrasound, the doctor will definitely evaluate the size of the fetal nuchal cavity. The thickness of the nuchal translucency space (TN) during normal development of the embryo should not exceed 3 mm. Too much fluid accumulation in this area leads to an increase in TVP and may be evidence of the presence of chromosomal abnormalities in the fetus, primarily Down syndrome. It is necessary to measure TVP precisely in the period from 10 to 14 weeks, since then studying this marker of chromosomal abnormalities will be ineffective. As a rule, doctors are guided by the following norms for TVP sizes, which differ according to the stage of pregnancy:

It should be remembered that the development of each child is an individual process and the deviation of the thickness of the collar zone from the norm is not a death sentence and does not provide grounds for establishing any final diagnosis.

Another important indicator for ultrasound examination is the biparietal size (BDS) of the fetal head. It is measured from temple to temple. This value also changes upward with each new week of pregnancy. Too large a BPR may be due to the following reasons:

  • the woman is carrying a large fetus (other sizes will also be higher than normal);
  • spasmodic growth of the embryo (in a couple of weeks the parameters will level out);
  • the fetus has a brain tumor or cerebral hernia (these abnormalities are incompatible with life);
  • hydrocephalus (dropsy) of the brain, which was the result of an infection suffered by the mother (with successful treatment with antibiotics, pregnancy can be saved).

Small BPD may indicate underdevelopment of the brain.

On an ultrasound of the first trimester, the specialist also notes the presence or absence of a nasal bone in the fetus. The absence of this indicator should alert the doctor, since it is in the presence of chromosomal abnormalities that ossification of the fetus occurs later.

Ultrasound examination allows obstetricians-gynecologists to identify a risk group among women expecting a child. First of all, this applies to those whose fetal parameters and ultrasound norms do not coincide. Pregnant women at risk are referred for more thorough examinations to confirm or exclude the possibility of having a child with a hereditary pathology.

Ultrasound screening at week 12 (as well as during the entire first trimester) rarely allows you to accurately determine the sex of the child. Some medical centers offer expectant parents to record a memorable video with their baby.

Biochemical screening

The second important stage that is included in genetic screening during pregnancy is a hormonal (biochemical) assessment. To undergo this diagnosis, a pregnant woman simply needs to donate blood from a vein. This must be done in the coming days after the ultrasound procedure. No special preparation is needed for the analysis, but it is advisable to exclude fatty foods from the diet one day before blood sampling, do not smoke 30 minutes before the test, and avoid physical and mental stress. Pregnant women often ask the question: is it possible to eat before screening? It is best to refrain from eating before drawing blood, as even a light breakfast can distort the test results.

A general blood test in the first trimester is prescribed to absolutely all pregnant women. What does this analysis show? Firstly, it allows you to identify the presence of diseases, including sexually transmitted diseases, which can cause severe pathologies of the fetus: rubella, viral hepatitis B, chlamydia, etc. The following indicators are also necessarily studied:

  • Blood glucose level

    This parameter helps to prevent and promptly notice the onset of gestational diabetes mellitus. Timely prescribed treatment and diet will help avoid complications during pregnancy and the occurrence of pathologies in the fetus.

  • Blood protein level

An increased level of protein in the blood may indicate pathologies of the mother’s urinary system and kidneys, and possibly the development of preeclampsia.

As part of prenatal screening, the concentration of certain hormones is assessed, the level of which increases in a woman during pregnancy. In the first trimester, screening evaluates the following indicators: free b-hCG and plasma protein-A (PAPP-A). What it is?

Human chorionic gonadotropin (hCG) is a hormone that is produced by the placenta during pregnancy and is one of the most important indicators of a favorable pregnancy. Each week of pregnancy has its own normal concentration of hCG in the mother’s blood:

If the pregnancy is not multiple, then an elevated hCG level may indicate the following:

  • there is a high probability of the fetus having Down syndrome;
  • there may be a hydatidiform mole or choriocarcinoma (a rare cancer).

A reduced concentration of b-hCG in the first trimester may indicate the following dangerous conditions:

  • Edwards syndrome or Patau syndrome in the fetus;
  • ectopic pregnancy;
  • placental insufficiency
  • threat of spontaneous abortion;

PAPP-A (pregnancy associated protein A). This protein is produced by the fetal trophoblast, and its concentration in maternal blood in the early stages increases every week of pregnancy. Clinical studies have long confirmed that PAPP-A levels are an excellent marker for detecting a high risk of chromosomal abnormalities in the fetus, which helps detect severe diseases in the early stages of pregnancy. Each week of pregnancy has its own normal level of PAPP-A:

The most dangerous condition is precisely the decrease in PAPP-A relative to the norm. This may indicate the following abnormalities:

  • development of one of the chromosomal abnormalities: Down syndrome, Edwards syndrome or Cornelia de Lange syndrome;
  • spontaneous miscarriage or intrauterine fetal death.

What does elevated PAPP-A levels indicate? In general, if other indicators are normal, such a deviation should not cause much concern. It has been proven that pregnant women with elevated PAPP-A levels have no higher risk of fetal malformations and complications during pregnancy than women with normal PAPP-A levels. An increase in the concentration of this hormone can be justified by the following reasons:

  • a woman carries several fetuses (twins/triplets);
  • the fetus is large in size, and the mass of the placenta is increased;
  • low location of the placenta.

After the 14th week of pregnancy, you should not take a PAP-A test, as it will be considered uninformative.

When screening diagnostics in the first trimester, specialists consider both indicators (b-hCG and PAPP-A) in combination. If PAPP-A is reduced and b-hCG is simultaneously increased, the doctor will most likely suspect the presence of Down syndrome in the fetus. A decrease in both markers may indicate the presence of Edwards syndrome or Patau syndrome.

There is a possibility that the blood test may give false values. The reasons for distorted results may be:

  • obesity, which causes hormonal levels to become unstable;
  • fertilization using IVF. PAPP-A will be lower by 10-15%, hCG will be increased, and ultrasound will show an increase in the fronto-occipital size of the fetus.
  • multiple pregnancy.
  • stressful state of a woman.
  • diabetes.

After undergoing an ultrasound procedure and donating blood for biochemical markers, the risk of chromosomal abnormalities in the fetus will be calculated for the expectant mother. The results of the 1st trimester screening (ultrasound, the level of biochemical markers in the blood) and the mother’s personal data will be entered into a special program. The following is indicated as personal data:

  • age of the pregnant woman;
  • date of blood sampling, date of ultrasound and gestational age;
  • number of fruits;
  • the mother has type 1 diabetes mellitus);
  • body weight of the female patient;
  • patient's ethnicity;
  • does the woman smoke during pregnancy?
  • pregnancy occurred naturally or through the use of assisted reproductive technologies (IVF).

After processing the data, the program displays the risk of gene abnormalities in numerical form, for example, 1:1900. This would mean that for every 1,900 women with the same screening characteristics, there could be one case of having an affected child. A screening result of 1:100 in Russia will be considered a high risk threshold. The complex of all screening studies makes it possible to detect Down syndrome with 85% confidence.

The identified high risk of Down syndrome according to the first screening is not such a rare occurrence. However, it is worth understanding that deciphering the screening results is not a final diagnosis or a verdict, but only the estimated risk of pathology! If it happens that the 1st trimester screening shows disappointing results, then the woman will need to seek professional advice from a geneticist, who will most likely prescribe a more thorough examination for the pregnant woman. It usually consists in the use of invasive diagnostic methods: chorionic villus biopsy (at 10-13 weeks of pregnancy) or amniocentesis (16-17 weeks of pregnancy).

Both of these procedures involve surgery and are performed in a hospital setting. Under the supervision of an ultrasound machine, a specialist punctures the mother’s anterior abdominal wall and collects material containing fetal DNA. In the case of chorionic villus biopsy, these are pieces of placental tissue; in amniocentesis, these are amniotic fluid (amniotic fluid). The study of the obtained biomaterials allows us to determine with high accuracy (about 99%) the presence or absence of chromosomal abnormalities and congenital diseases in the fetus.

However, these methods have their significant drawbacks - they are quite unpleasant and cause stress for the woman. In addition, there is a risk of spontaneous miscarriage (in approximately 1.5% of cases) caused by these procedures. Occasionally, invasive diagnostics lead to complications during pregnancy, which are expressed in leakage of amniotic fluid, bleeding, injury to the fetus, etc.

Modern medicine also offers alternative, safe methods of highly accurate prenatal diagnostics. One such method is a non-invasive prenatal DNA test based on modern molecular technologies. The test has long been successfully used in medical centers abroad and is becoming increasingly in demand among Russian doctors. The test process is as follows:

  • a pregnant woman donates blood from a vein;
  • fetal DNA is isolated from the obtained material using the sequencing method;
  • the genetic material of the fetus is analyzed for the presence of chromosomal pathologies and some hereditary diseases;
  • future parents are provided with a detailed transcript of the analysis results.

This non-invasive technique has an accuracy of over 99%, which significantly exceeds the accuracy of the combined analysis of screening tests (ultrasound and biochemical blood tests). As a result, some modern mothers prefer this test to traditional screening, although it is somewhat more expensive. The advantage of the method is that already in the ninth week of pregnancy it can detect a wide range of gene abnormalities and hereditary diseases in the fetus. For many expectant mothers, this test allowed them to avoid unsafe invasive diagnostics, and simply helped them gain confidence in the health of their unborn child. In addition, thanks to this method, you can find out the sex of the fetus.

Favorable results from a non-invasive DNA test provide an almost 100% guarantee that the fetus does not have the chromosomal abnormalities for which its DNA was tested. If the result indicates a high risk, the woman will still have to undergo an invasive examination, since only the conclusion of the invasive diagnostics can be the basis for an abortion for medical reasons.

In cases of poor results from invasive tests, doctors will most likely recommend that the woman have an abortion for medical reasons. In some cases, such a measure will be truly justified and reasonable action. However, no one has the right to force a pregnant woman to take such actions; the decision in any case must be made by the woman herself and her family. It is worth understanding that any decision in this case must be balanced and well thought out. Many people underestimate all the hardships and trials that they will have to endure if they agree to give birth to a baby with severe defects.

Where to do 1st trimester screening?

questions about screening that concern expectant mothers: how screening is done at 12 weeks, where to do 1st trimester screening in Moscow, how much does the first ultrasound cost, what is the price in Moscow for biochemical screening, etc. etc.

Naturally, the price for 1st trimester screening will differ significantly depending on what city the expectant mother lives in and how prestigious a medical center she chooses for this examination. It is advisable to contact institutions that specialize in genetic research.

Is it worth getting 1st trimester screening?

Alas, even the healthiest parents are not immune from the birth of a child with severe defects. The well-known Down syndrome, for example, can occur due to an accidental error during the division of maternal or paternal cells. It is not possible to influence it during pregnancy, since the mechanism for the development of the anomaly starts already at the moment of conception. Many people also carry genetic abnormalities without even knowing it. This is revealed only when a sick child is born into the family. Based on at least these two factors, a pregnant woman should not avoid screening in the first trimester.

Of course, it is worth knowing that many patients are dissatisfied with the quality of screening calculations. Often, in cases of high screening risk, healthy babies were born, and poor screening results forced the woman (if she refused invasive diagnostics) to be in a stressful state during pregnancy.

There are quite a lot of families who are ready to accept and raise a child even with severe disabilities. In this case, you can refuse to undergo screening, but first you should soberly weigh your moral and financial capabilities, and also find out as much information as possible about congenital defects and genetic anomalies.

If a married couple realizes that it is extremely important for them that the baby is healthy and able to lead a full life, then 1st trimester screening should be included in the list of prenatal examinations for the woman. An identified high risk of pathologies will be a reason for more careful monitoring by a gynecologist and a geneticist, and a low risk will allow you to enjoy your pregnancy without unnecessary worries.