Trisomy 21 normal values ​​at 35. First trimester screening: results, risk calculation

Chromosomes are structural elements of the cell nucleus and carriers of gene information. The normal human chromosome set consists of 23 pairs of homologous chromosomes (46 pieces). Trisomy is a change in the amount of chromosomal material in the direction of its increase, that is, a third, extra one appears in a pair of chromosomes. Excess genetic material leads to severe consequences to health, and in many cases even fatal. One of these severe gene pathologies is trisomy 18 (Edwards syndrome). It is detected in approximately one in 5,000 newborns; in 80% of cases, girls are affected.

Let's take a closer look at what trisomy 18 is, how it can be diagnosed and what is the prognosis for the life of people with this chromosomal abnormality.

Causes of trisomy 18

In the vast majority of cases, trisomy 18 is explained by the occurrence of an accidental defect in the process of formation of an egg or sperm, which leads to the formation of an additional copy of chromosome 18. Thus, in each cell of the body there are three copies of chromosome 18, instead of two. Moreover, 90% of the anomaly is explained by maternal origin.

All these methods are carried out using surgical intervention, which involves puncture of the mother’s abdominal wall for the purpose of collecting required material. Invasive diagnostics are highly accurate (about 99%), but cannot guarantee absolute safety. In some cases, invasive procedures can even cause miscarriage (about 1.5% chance). Other complications may occur: bleeding, leakage amniotic fluid, fetal injury, etc., although the likelihood of this is low.

Modern medicine several years ago, she began introducing methods that help high-risk women avoid unsafe and unpleasant invasive diagnostics. They can also be used by absolutely any pregnant woman without any special indications. This diagnostic method is called a non-invasive prenatal DNA test. It only involves taking blood from a vein from the expectant mother. The technique is effective already from the 9th week of pregnancy and with high accuracy (more than 99%) identifies a wide range of chromosomal abnormalities, including trisomy 18. The interpretation of the test will also indicate the degree of risk of pathology. In case of high risk, the pregnant woman will still have to undergo invasive diagnostics, since only the conclusion of an invasive study can serve as admission to an abortion for medical reasons.

Everyone knows, but not everyone knows, that this disease is also called trisomy 21, since it is in this pair of chromosomes that extra cells appear. This is the most common chromosomal pathology, so it has been most fully studied by scientists.

All women have a risk of developing trisomy 21 pairs of chromosomes in the fetus. It averages 1 case in 800 pregnancies. It increases if the expectant mother is under 18 years old, or already over 35 years old, and also if there are cases of children with deviations at the gene level in the family.

To identify this anomaly, it is recommended to undergo a combined test consisting of a blood test and an ultrasound examination. The result obtained is to determine the likelihood of trisomy 21 in a baby still in the womb. But it is not always possible to understand the information issued by the laboratory; for this you need to go to the doctor, which is often impossible to do right away.

In order not to torment yourself with guesswork and worries, from this article you will learn what the basic and individual risk of trisomy 21 mean and how to decipher their meanings.

Basic risk norm for trisomy 21

The basic risk of developing Down syndrome refers to the proportion indicating how many expectant mothers with the same parameters there is one case of this anomaly. That is, if the indicator is 1:2345, then this means that this syndrome occurs in 1 woman out of 2345. This parameter increases depending on age: 20-24 - over 1:1500, from 24 to 30 years - up to 1 :1000, from 35 to 40 – 1:214, and after 45 – 1:19.

This indicator was calculated by scientists for each age; it is selected by the program based on data about your age and exact date pregnancy.

To obtain this indicator, you need ultrasound data performed during the period 11-13 weeks of pregnancy (the size of the collar zone in the child is especially important), a biochemical blood test and individual data of the woman (available chronic diseases, bad habits, race, weight and number of fetuses).

If trisomy 21 is above the cutoff ( basic risk), then this woman has high (or they also write “increased”) risk. For example: the basic risk is 1:500, then a result of 1:450 is considered higher. In this case, they are referred for a consultation with a geneticist, followed by invasive diagnostics (puncture).

If trisomy 21 is below the cutoff, then in this case low risk of this pathology. For more accurate results It is recommended to conduct a second screening, which is done at 16-18 weeks.

Even after receiving bad result, under no circumstances should you give up. It is better, if time permits, to retake the tests and not lose heart.

The main structural elements of the cell nucleus are called chromosomes. They are the ones who carry with them genetic information, which, transmitted from generation to generation, is responsible for development human body. The human chromosome set consists of 23 pairs of homologous chromosomes(total 46 pieces). Any excess or deficiency of chromosomal material in the body can have extremely Negative influence on health and vitality.

Trisomy is a condition when a third, extra one appears in a pair of chromosomes. Trisomy 13 (Patau syndrome) is one such gene abnormality. It occurs in approximately one in 7,000 to 14,000 newborns; both boys and girls are affected equally.

Let's consider what trisomy 13 is, what indicators are considered when diagnosing it, and whether there are methods to combat this gene pathology.

Causes of trisomy 13

In the vast majority of cases, trisomy 18 is explained by the occurrence of an accidental defect in the process of formation of an egg or sperm, which leads to the formation of an additional copy of chromosome 18. Thus, in each cell of the body there are three copies of chromosome 18, instead of two. Moreover, 90% of the anomaly is explained by maternal origin.

About 5% of people with Edwards syndrome have an extra copy of chromosome 18 in only some cells of the body. This condition is called mosaic trisomy 18.

Even less commonly, the disease occurs in the form of a balanced translocation. What does it mean? In this form, chromosome 18 moves to another chromosome and genetic material is exchanged between them, but this process does not involve the loss of genetic information. Typically, a person with a balanced translocation is not even aware of the rearrangement in his chromosomes, since it does not affect his health. Another thing is that such a feature of the genotype can affect the child of this person, manifesting itself in the form of an unbalanced restructuring.

The classic and mosaic forms of trisomy 18 are random events that occur as a result of an error during cell division and are not inherited.

Clinical manifestations of Patau syndrome

Most babies with trisomy 13 die within the first weeks of life. 95% do not live to see a year. Already at the birth of a child you can notice a large number of physical defects:

• body weight below normal
• microcephaly (reduction in the size of the skull and brain)
• impaired development of parts of the central nervous system
• low sloping forehead
• underdevelopment of the eyes (microphthalmia)
• corneal clouding
• wide nose
• ear deformation
• cleft lip
• Exceeding the normal number of fingers (polydactyly)
• short neck

Regarding severe developmental defects internal organs, then the following deviations are observed:

• cardiac developmental defects vascular system(in 80% of newborns)
• fibrocystic changes of the pancreas
• accessory spleen
• embryonic umbilical hernia
• kidney enlargement

Pathologies of the genital organs:

• micropenis and cryptorchidism (absence of a testicle in the scrotum) in boys
• duplication of the uterus or vagina in girls

Trisomy 13 in a newborn

For children who live to be 2-3 years old, trisomy 13 results in severe mental retardation.

How is trisomy 13 diagnosed?

Pregnancy with a fetus with trisomy 13 often ends in miscarriage, which occurs in the 1st trimester. This is how the mother’s body gets rid of the non-viable fetus. However, there is a chance that the pregnancy will end in a live birth of a child with this deviation. How to prevent the birth of a sick baby?

First of all, future mom must undergo prenatal diagnostics - pregnancy screening. During the entire period of gestation, screening is carried out three times. These studies allow us to calculate the probability that the fetus is a carrier of genetic abnormalities.

The first screening is usually carried out at 12-13 weeks. First the woman passes ultrasonography(ultrasound), and then donates blood for biochemical analysis.

Ultrasound is a universal procedure that allows one to identify signs of severe disorders in fetal development. Patau syndrome can be suspected during ultrasound by the following features:

• 70% of fetuses experience rapid heart rate (tachycardia);
• increased bladder size);
• a combination of disorders of brain formation with omphalocele (extension of intestinal loops and other organs outside the abdominal cavity);
• developmental delay of the fetus.

In the 1st trimester, a pregnant woman donates blood to determine the concentration of biochemical markers in it: human chorionic gonadotropin (hCG) and pregnancy-associated plasma protein A (PAPP-A). For each of these markers, there are normative indicators that differ by week of pregnancy. The risk of trisomy 13 is characterized primarily by a sharp decrease in PAPP-A levels relative to normal levels.

The obtained ultrasound results, biochemical analysis, as well as the personal data of the pregnant woman (age, number of fetuses, chronic diseases, bad habits) are entered into a program that will calculate the basic risk of a chromosomal abnormality (the risk for women with similar characteristics) and the individual risk for specific pregnancy. If the frequency of an individual risk is less than the base one (for example, 1:5000 is the base risk, and 1:6980 is the individual risk), then this indicates a low risk of pathology. If on the contrary, this does not mean that the child is necessarily sick, but the pregnant woman will need to undergo genetic consultation and additional examinations.

Most likely, the woman will have to undergo one of invasive procedures, which allow you to study the DNA of the fetus and establish (or refute) a preliminary diagnosis with high accuracy (about 99%). The choice of method will depend on the stage of pregnancy:

These methods are carried out using surgical intervention: under the control of an ultrasound machine, a puncture of the mother’s abdominal wall is performed in order to collect the necessary material. Invasive diagnostics, alas, does not guarantee absolute safety for the mother and fetus. It is rare, but it happens that these procedures provoke a miscarriage (probability about 1.5%). The consequences of invasive research can also include pregnancy complications: bleeding, fetal injury, etc., although the likelihood of their occurrence is low.

Today, prenatal medicine is actively introducing safe methods, which help pregnant women at high risk of chromosomal abnormalities avoid unsafe invasive tests. This type of diagnosis is a non-invasive prenatal DNA test. The advantages of the method are obvious:

• effectiveness already at 9 weeks of pregnancy;
• identification wide range chromosomal abnormalities, including trisomy 13;
• safety and simplicity of the procedure for collecting material (blood sampling from the mother’s vein, from which fetal DNA will be isolated);
• high accuracy (more than 99%);
• opportunity to find out the sex of the child.

The interpretation of the test, as well as the screening results, will indicate the degree of risk of pathology. However, this will be much more reliable information. Low risk provides a high guarantee (about 100%) that the fetus does not suffer from abnormalities for which its DNA has been studied. If a high risk is identified, you will still have to undergo invasive research, since only the data obtained with the help of them can serve as the basis for an abortion for medical reasons.

Trisomy is the presence of several or one extra chromosome in the chromosome set. The most common variant is the presence on the 13th, 18th and 21st chromosomes.

Down syndrome

The second name for this disease is trisomy 21. Dr. Langdon Down was the first to study it in his practice and describe it in 1866. The doctor correctly stated the main fundamental symptoms, but he could not correctly determine the cause of this syndrome. Scientists were able to uncover the mystery of trisomy 21 only in 1959. It was then determined that this disease is of genetic origin. Copies of genes on chromosome 21 are responsible for the characteristics of the syndrome, namely the presence of an extra chromosome leads to such a pathology. It is known that each human cell contains twenty-three pairs of chromosomes. The first half comes through the egg from the mother, and the second half comes through the sperm from the father. But sometimes a malfunction occurs, and the chromosome may not separate, so one of the parents may get an extra unit. It is worth noting that boys and girls suffer from Down syndrome equally. The geographic location of the parents also does not matter. According to statistics, one in eight hundred children suffers from trisomy 21.

Causes and risk of trisomy 21. Normal risk indicators

The causes of Down syndrome are not yet fully understood. Scientists are still arguing about this pathology. The only thing they agree on is that trisomy 21 occurs as a result of the failure of multiple interactions between individual genes. And what she is not There is also a certain pattern: if the mother’s age exceeds 35 years, then the occurrence of this pathology increases by three percent. And what older age a woman giving birth, the higher the risk that the baby will have trisomy 21. Thus, the risk of giving birth to a sick child in women twenty-five years old is 1 child in 1250 children, and after forty - 1 child in 30 newborns. It should be noted that the age of the father does not affect the occurrence of the disease. A woman with Down syndrome can give birth to a sick child with a fifty percent chance; men with this disease are infertile. For parents who have a child with this pathology, the risk of trisomy 21 in their second child is one percent.

Methods for determining chromosomal abnormalities

Every woman planning a pregnancy worries about the health of her unborn baby. Modern medicine makes it possible to recognize many pathologies of child development in the womb. As mentioned above, the expected risk of trisomy 21 increases many times with increasing age of the mother. Therefore, those women whose age is at risk are prescribed screening in the first trimester of pregnancy. But not only age can be the reason why the doctor fears that the fetus may develop trisomy 21. The norm at which the test is prescribed:

• congenital pathologies during previous pregnancies, in particular chromosomal pathologies;
• presence of miscarriages;
• the presence of severe congenital diseases in relatives of the pregnant woman;
• transferred infectious diseases to early stages pregnancy;
• radiation exposure;
• birth of the first child with this syndrome;
• taking drugs with teratogenic effects in the early stages.

For analysis, blood is taken, and then the test sample is placed in a special apparatus, with the help of which the presence of pathology is detected. Trisomy 21 is also determined by indirect signs, normal indicators taken into account along with other objective factors. These include: the age of the woman in labor, weight, presence of fetuses, absence or presence bad habits and others. And only after it was carried out full examination, all risks are calculated, and the indicator “trisomy 21” is confirmed - the woman is invited for a consultation with a gynecologist, where she is told about the suspicion of Down syndrome in the unborn baby. A woman may decide to terminate her pregnancy. But screening results alone cannot provide a 100% diagnosis. If the analysis gives positive result, the doctor, as a rule, prescribes chorionic villus puncture.

Symptoms and signs of Down syndrome

As a rule, trisomy 21 is detected in the first minutes of a baby's life. There are a number external signs, according to which the doctor can diagnose this diagnosis. These include:

• short neck, flattened nose and face, small mouth, large, usually protruding tongue, Mongoloid small deformed ears;
• irregular palate, tongue with grooves, flat bridge of the nose;
• short and wide hands, palms with one fold, shortened phalanx of the middle finger;
• white spots on the iris of the eyes;
• low body weight;
• very weak muscle tone;

Pathology of internal organs

We can say that in people who have been diagnosed with trisomy 21, the rate of concomitant diseases is as follows:

Trisomy 21. Normal indicators of psycho-emotional manifestations

Perhaps the most common disorder in children diagnosed with this disorder is a disorder of psycho-emotional development. People with the pathology trisomy 21 are difficult to learn, they are not sociable, and have difficulty mastering speech. Often such children are either hyperactive or completely unsociable. These people are very susceptible to depression. But it should be noted that such children are very affectionate, obedient and attentive. They are also called “sunny children”.

Treatment of Down syndrome

Unfortunately, this pathology is currently incurable. The only way to help such people is to treat them. accompanying illnesses. In this way, you can extend the life of “sunny people” and improve the quality of life.

Down syndrome prognosis

Behind Lately The life expectancy of people with pathology on chromosome 21 has increased sharply. All thanks to improved quality of examinations and treatment. A person with this syndrome can live well up to fifty-five years or more. Thanks to integration into society, people with Down syndrome can live full life, children - go to regular schools. Today there are quite a lot of people who have managed to make a great contribution to social life and even become famous.

Parents who are told that their child has Down syndrome have many questions related to further care and raising a child. Until recently, our society was prejudiced against such people. This attitude has developed due to a lack of information. But lately, society has been receiving more and more information about people who are somewhat different from us. Now a large number of centers are being created where parents can come with their “sunny children”. In them they not only share their successes and experiences, but also teach children to adapt to everyday difficulties and join in modern society. It is important to do not only mental development child, but also physical. Good results give physical exercise and occupational therapy. It is necessary to teach the child to care for himself independently. It is very important to take care of a “sunny” child from infancy. There are many methods for the development of such children. And if close people help the child cope with his peculiarity, then there is a high probability that the child will be practically no different from his peers. He can not only go to a regular school, but also get a profession, which means he can become a full-fledged member of society.

Almost every pregnant woman has heard something about screening in the first trimester of pregnancy (prenatal screening). But often even those who have already completed it do not know what exactly it is prescribed for.

And for expectant mothers who are yet to do this, this phrase sometimes seems frightening. And it scares only because the woman does not know how this is done, how to interpret the results obtained later, and why the doctor needs this. You will find answers to these and many other questions related to this topic in this article.

So, more than once I had to deal with the fact that a woman, having heard the incomprehensible and unfamiliar word screening, began to draw terrible pictures in her head that frightened her, making her want to refuse to undergo this procedure. Therefore, the first thing we will tell you is what the word “screening” means.

Screening (eng. screening - sorting) is various methods studies that, due to their simplicity, safety and accessibility, can be used en masse among large groups of people to identify a number of signs. Prenatal means prenatal. Thus, we can give the following definition to the concept of “prenatal screening”.

Screening in the first trimester of pregnancy is complex diagnostic studies, used in pregnant women for certain period pregnancy, to identify gross malformations of the fetus, as well as the presence or absence indirect signs pathologies of fetal development or genetic abnormalities.

The acceptable period for screening in the 1st trimester is 11 weeks - 13 weeks and 6 days (see). Screening is not carried out earlier or later, since in this case the results obtained will not be informative and reliable. The most optimal period is considered to be 11-13 obstetric weeks pregnancy.

Who is referred for first trimester screening?

According to order No. 457 of the Ministry of Health Russian Federation Since 2000, prenatal screening is recommended for all women. A woman can refuse it, no one will force her to do this research, but doing this is extremely reckless and only speaks of the woman’s illiteracy and negligent attitude towards herself and, above all, towards her child.

Risk groups for whom prenatal screening should be mandatory:

• Women whose age is 35 years or more.
• The presence of a threat of termination of pregnancy in the early stages.
• History of spontaneous miscarriage(s).
• History of missed or regressed pregnancy(es).
• Presence of occupational hazards.
• Previously diagnosed chromosomal abnormalities and (or) malformations in the fetus based on screening results in past pregnancies, or the presence children born with such anomalies.
• Women who have had infection in the early stages of pregnancy.
• Women who took medications, prohibited for use by pregnant women in the early stages of pregnancy.
• Presence of alcoholism, drug addiction.
• Hereditary diseases in the family of a woman or in the family of the child’s father.
• I have a close relationship between the mother and father of a child.

Prenatal screening at 11-13 weeks of pregnancy consists of two research methods - ultrasound screening of the 1st trimester and biochemical screening.

Ultrasound examination as part of screening

Preparing for the study: If the ultrasound is performed transvaginally (the sensor is inserted into the vagina), then no special preparation is required. If ultrasound is performed transabdominal (the sensor is in contact with the anterior abdominal wall), then the study is carried out with full bladder. To do this, it is recommended not to urinate 3-4 hours before the test, or drink 500-600 ml of still water an hour and a half before the test.

Necessary conditions for obtaining reliable ultrasound data. According to the norms, screening of the first trimester in the form of ultrasound is carried out:

• No earlier than 11 obstetric weeks and no later than 13 weeks and 6 days.
• The CTP (coccygeal-parietal size) of the fetus is not less than 45 mm.
• The position of the child should allow the doctor to adequately take all measurements; otherwise, it is necessary to cough, move, walk for a while so that the fetus changes its position.

As a result of ultrasound The following indicators are studied:

• CTP (coccygeal-parietal size) – measured from the parietal bone to the coccyx
• Head circumference
• BDP (biparietal size) - the distance between the parietal tuberosities
• Distance from frontal bone to occipital bone
• Symmetry of the cerebral hemispheres and its structure
• TVP (thickness collar space)
• Fetal heart rate (heart rate)
• Shoulder length, femur, as well as the bones of the forearm and lower leg
• Location of the heart and stomach in the fetus
• Sizes of the heart and great vessels
• Placenta location and thickness
• Water quantity
• Number of vessels in the umbilical cord
• State internal pharynx cervix
• Presence or absence of uterine hypertonicity

Decoding of the received data:

What pathologies can be detected by ultrasound?

Based on the results of ultrasound screening in the 1st trimester, we can talk about the absence or presence of the following anomalies:

• – trisomy 21, the most common genetic disease. The prevalence of detection is 1:700 cases. Thanks to prenatal screening The birth rate of children with Down syndrome has decreased to 1:1100 cases.
• Developmental pathologies neural tube (meningocele, meningomyelocele, encephalocele and others).
• Omphalocele is a pathology in which part of the internal organs is located under the skin of the anterior abdominal wall in the hernial sac.
• Patau syndrome is trisomy on chromosome 13. The incidence is on average 1:10,000 cases. 95% of children born with this syndrome die within a few months due to severe damage to internal organs. Ultrasound shows increased fetal heart rate, impaired brain development, omphalocele, and delayed development of tubular bones.
• – trisomy on chromosome 18. The incidence rate is 1:7000 cases. It is more common in children whose mothers are over 35 years old. An ultrasound shows a decrease in the fetal heartbeat, an omphalocele, the nasal bones are not visible, and one umbilical artery instead of two.
• Triploidy is a genetic abnormality in which there is a triple set of chromosomes instead of a double set. Accompanied by multiple developmental defects in the fetus.
• Cornelia de Lange syndrome– a genetic anomaly in which the fetus experiences various developmental defects, and in the future, mental retardation. The incidence rate is 1:10,000 cases.
• Smith-Opitz syndrome– an autosomal recessive genetic disease manifested by metabolic disorders. As a result, the child experiences multiple pathologies, mental retardation, autism and other symptoms. The average incidence is 1:30,000 cases.

Learn more about diagnosing Down syndrome

Mainly, an ultrasound examination at 11-13 weeks of pregnancy is performed to identify Down syndrome. The main indicator for diagnosis becomes:

• Neck space thickness (TNT). TVP is the distance between soft tissues neck and skin. An increase in the thickness of the nuchal translucency may indicate not only an increase in the risk of having a child with Down syndrome, but also that other genetic pathologies in the fetus.
• In children with Down syndrome, it is most often not visualized at 11-14 weeks. nasal bone. The contours of the face are smoothed.

Before 11 weeks of pregnancy, the thickness of the nuchal translucency is so small that it is impossible to adequately and reliably assess it. After the 14th week, the fetus develops a lymphatic system and this space can normally be filled with lymph, so the measurement is also not reliable. The incidence of chromosomal abnormalities in the fetus depending on the thickness of the nuchal translucency.

When deciphering the screening data of the 1st trimester, it should be remembered that the thickness of the nuchal translucency alone is not a guide to action and does not indicate a 100% probability of the presence of the disease in the child.

Therefore, the next stage of screening of the 1st trimester is carried out - taking blood to determine the level of β-hCG and PAPP-A. Based on the obtained indicators, the risk of having chromosomal pathology. If the risk based on the results of these studies is high, then amniocentesis is suggested. This is taking amniotic fluid for a more accurate diagnosis.

In particularly difficult cases, cordocentesis may be required - taking cord blood for analysis. Chorionic villus sampling may also be used. All of these methods are invasive and carry risks for the mother and fetus. Therefore, the decision to perform them is decided by the woman and her doctor jointly, taking into account all the risks of carrying out and refusing the procedure.

Biochemical screening of the first trimester of pregnancy

This stage of the study must be carried out after an ultrasound scan. This important condition because everything biochemical parameters depend on the stage of pregnancy down to the day. Every day the norms of indicators change. And ultrasound allows you to determine the gestational age with the accuracy that is necessary for conducting a correct study. At the time of donating blood, you should already have ultrasound results with the indicated gestational age based on CTE. Also, an ultrasound may reveal a frozen pregnancy or a regressing pregnancy, in which case further examination does not make sense.

Preparing for the study

Blood is drawn on an empty stomach! It is not advisable to even drink water in the morning of this day. If the test is carried out too late, you are allowed to drink some water. It is better to take food with you and have a snack immediately after blood sampling rather than violate this condition.

2 days before the scheduled day of the study, you should exclude from your diet all foods that are strong allergens, even if you have never been allergic to them - these are chocolate, nuts, seafood, as well as very fatty foods and smoked foods.

Otherwise, the risk of obtaining unreliable results increases significantly.

Let's consider what deviations from normal levels of β-hCG and PAPP-A may indicate.

β-hCG – human chorionic gonadotropin

This hormone is produced by the chorion (“shell” of the fetus), thanks to this hormone it is possible to determine the presence of pregnancy in the early stages. The level of β-hCG gradually increases in the first months of pregnancy, its maximum level is observed at 11-12 weeks of pregnancy. Then the level of β-hCG gradually decreases, remaining unchanged throughout the second half of pregnancy.

PAPP-A – pregnancy associated protein-A

This is a protein produced by the placenta in the body of a pregnant woman, responsible for the immune response during pregnancy, and is also responsible for normal development and functioning of the placenta.

MoM coefficient

After receiving the results, the doctor evaluates them by calculating the MoM coefficient. This coefficient shows the deviation of the level of indicators in a given woman from the average normal value. Normally, the MoM coefficient is 0.5-2.5 (with multiple pregnancy up to 3.5).

These coefficients and indicators may differ in different laboratories; the level of hormone and protein can be calculated in other units of measurement. You should not use the data in the article as norms specifically for your research. It is necessary to interpret the results together with your doctor!

Further using computer program PRISCA, taking into account all the obtained indicators, the woman’s age, her bad habits (smoking), the presence diabetes mellitus and other diseases, a woman’s weight, the number of fetuses or the presence of IVF - the risk of having a child with genetic abnormalities is calculated. High risk is a risk less than 1:380.

Example: If the conclusion states high risk 1:280, this means that out of 280 pregnant women with the same indicators, one will give birth to a child with a genetic pathology.

Special situations when indicators may be different.

• IVF - β-hCG values ​​will be higher, and PAPP-A values ​​will be lower than average.
• When a woman is obese, her hormone levels may increase.
• In multiple pregnancies, β-hCG is higher and the norms for such cases have not yet been established precisely.
• Diabetes in the mother can cause hormone levels to rise.