Triple test, or "prenatal risk assessment": hCG, AFP and free estriol

modern medicine allows the expectant mother to learn more about the development of the baby. Screening or a triple test during pregnancy reveals the risks of developing pathologies in the fetus. It is carried out to confirm or refute the results of the first screening tests, as well as if there is an urgent indication for a triple test.

What is a triple test in the second trimester for?

Secondary screening is carried out at 16-20 obstetric week. It is at this time that right course pregnancy rates for most women are approximately the same. Week 18 is considered the most optimal.

The triple test consists of a population ultrasound diagnostics And biochemical analysis blood.

The study received this definition due to the analysis of 3 components of the blood of the expectant mother: hCG, ACE and free estriol. Together they give a general picture of the development of the fetus and possible risks abnormal deviation.

There is a group of pregnant women who are required to be screened:

Expectant mothers over the age of 35;
Couples who are closely related and expecting a baby;
Genetic disease of one of the parents;
Acute infection mothers at the beginning of pregnancy;
Previous frozen pregnancy, habitual miscarriage;
The birth of the first children with abnormal deviations;
Treatment medications prohibited during pregnancy;
Poor first screening result.

Before conducting the test, the expectant mother must refrain from eating citrus fruits, cocoa and chocolate, as well as exclude fatty, spicy and fried food. You need to take the test on an empty stomach. You can eat 6 hours before the tests.

What does the ACE test show?

All 3 tested hormonal components perform certain functions in the developing body of the child, and enter the mother's blood.

Alpha-fetoprotein, abbreviation AFP, is a protein produced by the baby's liver and involved in the formation neural tube. Once in the anatomical fluid, the hormone through the placenta enters the mother's bloodstream. Alpha-fetoprotein can be detected as early as 6 weeks of pregnancy. At various pathologies protein release increases significantly, which is diagnosed during the test.

Elevated levels of ACE in the blood can mean the development of the following defects:

kidney pathology;
Anomaly of overgrowth of the neural tube of the fetus;
Absence or overgrowth of the duodenum;
Damage brain.

At the same time, the indicators should be overestimated by 3 or more times from the statistical norm. A slight increase in AFP can be observed with oligohydramnios, possible miscarriage or death of the fetus.

For women with multiple pregnancies increased results AFPs are the norm.

A low level of AFP is typical for women suffering from diabetes, obesity or with a low location of the placenta. If low AFP is combined with serious changes in other indicators, there is a risk of having a child with chromosomal abnormalities.

What the Scores Tell You: The Triple Test for Risk of Genetic Disorders

HCG level - chorionic gonadotropin human, is also important for determining the risks of genetic disorders. The hormone begins to be released after the embryo attaches to the uterine wall. Its amount increases, concentrating as much as possible on 6-7 weeks, then the level gradually drops. HCG is a protein produced by the placenta, which characterizes its condition.

Low human gonadotropin in the second trimester may indicate the following abnormalities:

placental insufficiency;
dangers of miscarriage;
Fetal death.

Overestimated parameters indicate an incorrectly established gestational age, toxicosis and diabetes of the mother, as well as gestosis of the fetus.

High hCG in combination with reduced levels of AFP and free estriol indicates a high risk of developing Down syndrome in the fetus.

Free estriol (EZ) is a female sex hormone produced by the liver and placenta of the fetus. It controls the process of growth of the uterus and placenta, improves the blood supply to the genital organs. E3 gives a large number of information about the course of pregnancy and fetal development.

A low level of estriol may indicate various threats:

Not gestation;
placental insufficiency;
Anemia in the fetus;
intrauterine infection;
CNS defects;
growth retardation;
Pathologies of the heart.

Underestimated rates can be observed with poor nutrition of the expectant mother or taking antibiotics.

An increase in estriol levels indicates big baby, multiple pregnancy or probabilities premature birth.

Reliability of Research: Quadruple Pregnancy Test

To confirm or deny risks genetic anomaly specialists can do a more detailed quadruple pregnancy test. Dates are scheduled in the second trimester. An additional study of inhibin A is added to the triple test, female hormone, which increases during pregnancy. IN normal condition in women, it is produced by the ovaries, in expectant mothers by the placenta and the embryo.

The value of inhibin A indicators:

There is a risk when it goes up chromosomal abnormalities fetus, Down's syndrome and hydatidiform mole;
Lower results indicate a risk of spontaneous abortion;
The norm is 2.0 MOM.

The fourth test must be supplemented ultrasound diagnostics fetus. At high risks additional studies are prescribed to confirm chromosomal pathology.

The deviation of one of the tested indicators does not mean an anomaly in the development of the child. Only the totality of all tested analyzes that indicate a certain deviation may have risks of a genetic disorder.

Expectant mothers must be prescribed dads - tests that are carried out 3 times during pregnancy. The Pap test is a cytology smear taken from the surface of the cervix. Laboratory analysis reveals different kinds infections: papillomavirus, chlamydia, trichomoniasis, gonorrhea, the presence of cancer cells. Timely detected and cured infections will not have time to harm the fetus.

Another method for the necessary diagnostics is a sail - a test that allows you to detect violations of the production of protein C, which affects the functioning of the hemostasis system - blood clotting. Its deviation can lead to abortion, placental thrombosis, bleeding.

What is a triple pregnancy test (video)

Tests and analyzes will help a pregnant woman dispel fears, and if markers of genetic pathologies are found, undergo additional examinations. It should be noted that with the help of testing it is impossible to make an accurate diagnosis. They only allow you to identify a risk group.

Triple test, or " prenatal assessment risk": hCG, AFP and free estriol

The main purpose of blood tests during pregnancy is determination of the risk of pathologies in the fetus. "Triple test" is the delivery of a blood test of a pregnant woman for hCG level, AFP and free estriol. The test is being conducted between , in the morning, strictly on an empty stomach. The doctor in the antenatal clinic is obliged to send the expectant mother to this study. A special program calculates the risk of having a child with Down's disease, the risk of DZNT (this abbreviation refers to certain groups of congenital malformations) and the risk of fetal growth retardation. As a result, you are given the result, where incomprehensible numbers and letters are written.

So, let's figure out what all these abbreviations, numbers, letters mean and what their meaning is for us.

HCG is human chorionic gonadotropin, it begins to be released in the woman's body immediately after the embryo attaches to the wall of the uterus (this happens approximately on the fourth or fifth day after fertilization). HCG is a placental protein, the level of which characterizes the state of the placenta at a particular stage of pregnancy, it can change if the fetus (and, accordingly, in the placenta) has chromosomal abnormalities. The protein level can also reflect the presence of a threatened miscarriage, changes in the placenta due to infection, immunological conflict, and other reasons. An altered level of hCG can also be observed during a normal pregnancy (!).

If hCG is low (hCG levels for each period, see below), this may indicate a threat of interruption (if the hormone level decreases progressively, by more than 50% of the norm), chronic placental insufficiency, about prolongation of pregnancy, as well as about antenatal death of the fetus.
If hCG is high, this may indicate a multiple pregnancy (the level of the indicator increases in proportion to the number of fetuses), prolonged pregnancy, a discrepancy between the real and due date pregnancy, toxicosis, preeclampsia, maternal diabetes, taking synthetic progestogens (hormones that contribute to the normal course of pregnancy). High hCG can also indicate the presence of Down syndrome in the fetus, but only in combination with reduced levels of AFP and free estriol!

AFP stands for Alpha Fetoprotein. This is a protein product that is produced by the baby's liver and enters the mother's bloodstream during pregnancy. Determination of its level is used to exclude the development of neural tube defects in the fetus, various sites digestive tract, urinary system, as well as Shershevsky-Turner syndrome (an incurable chromosomal disease characterized by birth defects hearts and others internal organs, infertility; sometimes - a decrease in mental development), a serious delay in the development of the fetus, certain diseases of the placenta and, finally, Down's syndrome.

Low AFP (the normal level for each period, see below) occurs with Down syndrome in the fetus, with a low placenta, obesity, the presence of diabetes mellitus in a pregnant woman, hypothyroidism and some other diseases, as well as during a normal pregnancy (!). There is also a dependence of the AFP level on race.
If AFP is high, this may mean that the child may be injured nervous system: softening of the spine, absence of the entire brain or parts of it. With such a pathology, a child can be born with paralysis of the lower half of the body and anencephaly (a disease in which the child's brain is seriously underdeveloped or does not develop at all). Also, an increased level of AFP is observed with an unfavorable course of pregnancy, the threat of termination, Rhesus conflict, oligohydramnios, intrauterine fetal death. Enhanced level AFP in multiple pregnancy is a physiological norm.

E3 or free estriol is a female sex hormone produced by the placenta and liver of the fetus. With the course of pregnancy, the level of estriol in the blood of a woman gradually increases. Estriol improves blood flow through the vessels of the uterus, promotes the development of mammary ducts during pregnancy. A decrease or a sharp decrease in estriol (by 40% or more) indicates pathological condition fetus.

Low level estriol may indicate a threat of miscarriage or premature birth, postmaturity, fetoplacental insufficiency, fetal hypotrophy (retardation of the rate of physical growth of the fetus), Rhesus conflict, anemia in the fetus (decrease in hemoglobin), o intrauterine infection, adrenal hypoplasia, fetal anencephaly (CNS defects), heart defects, and Down syndrome. Also, a low level of free estriol can be observed in a future mother with malnutrition, as well as when taking antibiotics.
If estriol is high it most often refers to large fruit or multiple pregnancy, can also talk about liver diseases, and only with a sharp (!) rise in the hormone - about the likelihood of premature birth.
The content of serum markers in the blood of pregnant women varies in accordance with the gestational age, each laboratory uses its own standards depending on the type of reagents used. When evaluating the results, you need to rely only on the standards of the laboratory where you underwent the analysis !!! For the convenience of assessing the level of serum markers, the values are usually expressed in relative units - MoM (multiples of median - a multiple of the average value). The norm in MoM for any serum marker at any stage of pregnancy is 0.5-2.0 MoM.

A change in only one of the indicators of the "triple test" is not significant, a comprehensive analysis is always necessary. A correct estimate of the result can be obtained by using computer programs calculation of genetic risk, which take into account the individual indicators of each patient - age, weight, ethnicity, the presence of certain diseases, ultrasound data. And even the results of computer calculations do not serve as a diagnosis of the disease, but only represent a statistical assessment of individual risk.

Below is an indicative hCG norm, AFP and E3. But, as mentioned above, laboratories use different units of measurement, and often indicators of the norm are indicated next to the result.

The normal level of hCG in the blood serum of pregnant women can be determined from the following table:

Gestational age (weeks)	Median (average value)	Norm
1-2	150	50-300
3-4	2000	1500-5000
4-5	20000	10000-30000
5-6	50000	20000-100000
6-7	100000	50000-200000
7-8	70000	20000-200000
8-9	65000	20000-100000
9-10	60000	20000-95000
10-11	55000	20000-95000
11-12	45000	20000-90000
13-14	35000	15000-60000
15-25	22000	10000-35000
26-37	28000	10000-60000

The content of estriol (E3) in the blood of pregnant women:

week of pregnancy	Estriol concentration (nmol/l)
12	1,05-3,5
13	1,05-3,85
14	1,4-5,6
15	3,5-15,4
16	4,9-22,75
17	5,25-23,1
18	5,6-29,75
19	6,65-38,5
20	7,35-45,5

The content of alpha-fetoprotein (AFP) in the blood of pregnant women:

week of pregnancy	Average value (median) IU/ml
14	26,0
15	30,2
16	34,4
17	39,0
18	44,2
19	50,2
20	57,0

The triple test is physically safe for both mother and fetus. The only danger is unnecessary worries and worries. The main drawback of the study is its, to put it mildly, inaccuracy. Now experts are talking about 80% of false positive results (according to the official version, 5%). For example, false positive result quite possible if wrong a certain period pregnancy, deviations in the weight of the mother, the presence of diabetes in the mother.
Only your personal doctor can evaluate the test results: only he can see all the nuances of the test! So, in order for the doctor to suspect a genetic pathology in the fetus, it is necessary that the triple test indicators be several times higher or lower than normal, but minor changes in the indicators, as a rule, are the reason for re-testing.
Dear future mothers! Remember one simple thing: With the help of this study, it is impossible to accurately diagnose! It only allows you to identify pregnant women at risk who need a serious additional examination! Therefore, when a positive result a triple test, do not despair and do not jump to conclusions!

Any woman who is registered with the clinic is required to pass the "triple test". This procedure consists in taking a blood test in the morning on an empty stomach, which is necessary to determine the level of hCG, free estriol and AFP.

These three indicators help determine the risk of developing certain groups of heart defects, as well as a number of other developmental pathologies. However, even the "abnormal" indicators of the triple test do not always indicate wrong development fetus.

As a conclusion, doctors give out a piece of paper covered with incomprehensible abbreviations and numbers that do not tell the woman anything.

We suggest that you do not worry in advance, but simply try to sort out the results yourself first. We also remind you that not a single table will give you a "diagnosis", and this article is necessary solely to calm a pregnant woman who is excited about a triple unfolded test.

To understand the medical subtleties, we provide a glossary of terms and special tables that help you not to get confused in the numbers.

Glossary of terms:

HCG or human chorionic gonadotropin is a placental protein that begins to enter the body of a pregnant woman in large quantities already 4-5 days after fertilization. By the way, all home pregnancy tests respond specifically to the level of hCG, which is contained in urine and blood. The amount of hCG in the blood and urine depends not only on the course of pregnancy, but also on the timing. So, for example, a double and a triple test show different results already because they are carried out in different trimesters pregnancy.

AFP or alpha-fetoprotein is a protein substance that is a product of the functioning of the fetal liver. This indicator is included in the results of the triple test in order to determine the risk of improper (defective) development of the child's digestive tract, neural tube, and genitourinary system. AFP also helps to eliminate Shershevsky-Turner syndrome - a chromosomal disease characterized by defects in internal organs (including heart disease), infertility, sometimes delayed mental development. AFP can become one of the grounds for suspecting placental diseases, Down syndrome.

Free estriol is a sex hormone, the level of which should increase during pregnancy. Produced directly by the baby's liver and placenta. Estriol is necessary for the development of mammary ducts in the mother during pregnancy. The hormone has a positive effect on blood flow through the vessels of the uterus. Please note that only a sharp decrease in the level of free estriol by more than 40% indicates a probable pathology of the fetus.

You should not independently decipher the triple test, and then refuse to visit the doctor - only he can reliably tell about the condition of the fetus and placenta.

Low levels of hCG, estriol, AFP

Reduced hCG may indicate a threat of termination of pregnancy only when the level of the hormone progressively "leaves" more than 50% of the norm. This is another reason to pay attention to the fact that with a triple test, the concept of the norm is very vague, and significant deviations of indicators are necessary for real conclusions.

A serious decrease in hCG may indicate a risk or placental insufficiency, and occasionally antenatal fetal death.

Low AFP may indicate not only pathologies in the fetus, but also some diseases in a pregnant woman. For example, it is often noted in obese or diabetic patients. In combination with "wrong" other indicators, low AFP indicates the risk of having a child with Down syndrome.

Sometimes a deviation from the norm in the results of a triple test during pregnancy occurs even during its normal course.

Decreased free estriol sometimes speaks of a threat or, overcarrying or placental insufficiency.

In the fetus itself, low estriol may reveal a risk of - delayed physical development, heart disease, anencephaly, adrenal hypoplasia or anemia.

Sometimes low estriol indicates the risk of having a baby with Down syndrome, but all indicators should indicate this. triple screening complex test. Doctors never make conclusions on one indicator.

Also, a downward deviation from the norm sometimes occurs with improper or inadequate nutrition of the expectant mother.

Elevated levels of hCG, estriol, AFP

In the happiest situations high hCG can even talk about the absence of complications during pregnancy. So, a triple test always shows elevated hCG.

Sometimes hCG is "falsely elevated" - with wrong definition gestational age or prolonged carrying of the fetus.

By the way, a triple test designed for 16 weeks cannot give correct results for gestational age above 18 weeks.

High hCG is noted in patients with diabetes mellitus, suffering from or.

An increase in placental protein occurs when a woman takes gestagens - hormones necessary for normal course pregnancy. In combination with low AFP and estriol, high hCG indicates the risks of having a baby with Down syndrome.

Elevated AFP may indicate serious damage to the fetal nervous system: complete or partial anencephaly, softening of the spine.

High AFP sometimes indicates an Rhesus conflict, intrauterine fetal death, or.

However, AFP and a triple detailed test are unreliable in case of a previously undiagnosed multiple pregnancy, and an increase in all its indicators in this case is the norm.

high estriol - the most harmless deviation, which is most often found in the development of a very. Also, a triple test with multiple pregnancies always shows higher estriol. And only in the case of a sharp and very strong upward deviation, there is a risk of premature birth.

It is important to know

Please note that the results of a triple test during pregnancy in different laboratories can vary greatly, just because each of them has its own norms!

To make the assessment easier and more convenient, the values of serum markers are expressed in units of MoM. For any serum marker, the normal MoM is 0.5-2.0 at any stage of pregnancy.

If prenatal biochemical screening (triple test) was not performed on an empty stomach, then its results are considered invalid, and the woman must be tested again.

Remember that a triple test during pregnancy may indicate serious problems only if all three indicators deviate significantly from the norm indicated in the table. Moreover, taking a triple pregnancy test, which is relatively affordable, is only necessary to obtain statistical data that determine possible pathologies and diseases!

A correct assessment of the results can be made only with the help of special computer programs that calculate genetic risks. The programs take into account not only the analysis indicators and the timing of pregnancy, but the ethnic group of the woman (estrogiol in different nationalities different), weight and age, presence chronic diseases, recent ultrasound findings.

But this is not a guarantee of reliability, because the triple test does not determine the timing, and the erroneous diagnosis of the gestational age is by no means a common occurrence. Sometimes serious deviations from the norm may turn out to be a mistake, and this is partly why the results of such a test cannot form the basis for any diagnosis.

Triple test: detection of fetal malformations

Who will be born to you? Girl or boy?
Are you doing everything right so that the pregnancy proceeds without complications?

Each future mom worried about the health of her baby. Is it possible to early dates pregnancy to find out if everything is in order? Modern medicine answers this question in the affirmative. At the disposal of obstetricians-gynecologists and geneticists are many diagnostic methods, allowing with a high probability to judge the presence of malformations when the child is in the womb. The chances of accuracy are increasing due to advances in ultrasound technology and laboratory diagnostics. And in last years the so-called triple test is increasingly being used.

This method involves the study of markers of malformations and genetic pathology fetus: alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG) and estriol (E3).

"Three whales" research

AFP is the main component of the liquid part of the blood (serum) of the developing fetus. This protein is produced yolk sac and fetal liver, goes into amniotic fluid with his urine, enters the mother's blood through the placenta and is absorbed membranes. By examining the blood from the mother's vein, one can judge the amount of alpha-fetoprotein produced and secreted by the fetus. AFP is found in the mother's blood from the 5th to 6th week of pregnancy. The amount of AFP in the mother's blood changes with a more massive release of this component. So, if any parts of the neural tube are not closed, a larger amount of the baby's serum is poured into the amniotic cavity and enters the mother's blood.

Elevated AFP content is determined in maternal blood:

* with defects in the fusion of the neural tube - a hernia of the spinal cord or brain,
* with defects in the fusion of the anterior abdominal wall, when its muscles and skin do not cover the internal organs, and the intestines and other organs are covered with a thin film of the stretched umbilical cord (gastroschisis);
* with anomalies of the kidneys;
* when the duodenum is infected.

It must be said that an increase in the amount of AFP by 2.5 or more times compared with the average for this period pregnancy. So, for example, with anencephaly (absence of the brain), the level of AFP increases by approximately 7 times.

But a change in the level of AFP does not necessarily indicate any pathology of the fetus. It can also be observed in conditions such as the threat of termination of pregnancy in fetoplacental insufficiency, when blood flow between the placenta and the fetus is disturbed, as well as in multiple pregnancies, during which this protein is produced by several fetuses.

In 30% of cases of chromosomal disorders, when the fetus has additional chromosomes in one or another pair, which leads to the formation of multiple malformations (Down, Edwards, Shereshevsky-Turner syndromes), the AFP level is reduced.

HCG is a protein produced by the cells of the chorion (the chorion is the part of the embryo from which the placenta is later formed). This protein is detected in a woman's body from 10 to 12 days after fertilization. It is its presence that allows you to confirm the onset of pregnancy with a test at home. The reaction that occurs on the test strip is qualitative, that is, it indicates the presence or absence of hCG. quantitative determination of hCG allows you to judge the course of pregnancy: for example, with an ectopic or non-developing pregnancy the rate of increase in hCG does not correspond to the norm. At the beginning of the second trimester, the level of human chorionic gonadotropin is used as one of diagnostic signs malformations and chromosomal pathology of the fetus.

The level of hCG in the blood of a pregnant woman with Down syndrome usually increases, and with Edwards syndrome (a disease characterized by multiple malformations internal organs and mental retardation - decreases.

E3. Estriol production begins in the fetal liver and ends in the placenta. Thus, both the fetus and the placenta take part in the “production” of this substance. According to the concentration of E3 in the blood serum of a pregnant woman, one can judge the condition of the fetus. Estriol levels normally rise during pregnancy.
When, to whom and how the test is carried out

A triple test is carried out at a gestational age of 15 to 20 weeks. At this time, the indicators of markers of genetic pathology are the most standardized, that is, they are the same for all women whose pregnancy is proceeding normally. Many medical institutions are testing AFP and hCG ( double test) or only AFP. I would like to emphasize that in the study of any one component of the triple test, the diagnostic significance of the study decreases, since the deviation from the norm of only one of the indicators cannot reliably indicate fetal pathology. In general, the diagnostic value of the triple test is up to 90% for the detection of malformations of the nervous system, 60 - 70% - for the detection of chromosomal diseases.

Currently, examination for markers of genetic pathology is mandatory for all pregnant women, but, unfortunately, the equipment of ordinary state medical institutions (antenatal clinics) in most cases allows you to examine only one or two components of the triple test. If abnormalities are found, the patient is referred to a geneticist for further examination.

There is a group of pregnant women who are prescribed a genetic consultation regardless of the test results: this is the so-called risk group, in which the likelihood of children with congenital malformations and chromosomal pathology is higher than in the general population.

Risk factors include:

* the woman's age is over 35,
* cases of familial carriage of chromosomal diseases,
* the birth of previous children with malformations,
* radiation exposure of one of the spouses,
* taking cytostatics or antiepileptic drugs,
* habitual miscarriage,
* determination of signs of fetal pathology by ultrasound.

If deviations are found, it is advisable to repeat the analysis; if at the same time the indicators continue to decrease or increase, additional studies are carried out. It is better to take the test at the beginning of the specified period, i.e. at 15-16 weeks, in order to be able to repeat the examination if necessary and confirm or refute certain assumptions.

Of particular concern is a decrease in AFP in combination with a persistent increase in the level of hCG. This combination makes it possible to suspect the presence of Down syndrome in a child. But only in 60% of cases, women carrying a fetus with Down syndrome have pathological indicators of a triple test; in 40% of cases, there are no deviations in laboratory parameters.

It should be emphasized that the study of markers of genetic pathology is a screening, that is, it is carried out for all pregnant women to identify a risk group (in other words, you may not suspect that this analysis was taken from you as part of a general pregnancy examination).

Patients from the risk group undergo a more detailed diagnosis of fetal malformations, chromosomal pathology: as part of medical genetic counseling, they are prescribed an additional ultrasound examination, and offer methods of invasive (with penetration into the amniotic cavity) diagnostics. by the most authentic way diagnosis is the study of the chromosomal set of fetal cells. To obtain fetal cells, the anterior abdominal wall is pierced with a thin needle, amniotic fluid is taken, which contains fetal cells (amniocentesis) or umbilical cord blood of the fetus (cordocentesis). When carrying out invasive diagnostic methods, the risk of fetal loss increases significantly; in addition, as with any surgical intervention, there is a risk of infection. Therefore, invasive techniques are contraindicated in case of a threatened abortion and in acute infectious diseases.

Considering the time frame in which it is customary to produce a triple test, sometimes the question arises of the appropriateness of this analysis, because the timing of a medical abortion is limited to the 12th week. In this regard, it should be remembered that every woman who carries a baby under her heart at one stage or another of pregnancy is visited by doubts about the usefulness of the unborn child. A triple test will help you dispel unpleasant thoughts, and if changes in markers of the genetic pathology of the fetus are detected, additional examinations will be completed on time. If unpleasant assumptions are confirmed, it will be possible to terminate the pregnancy, or at least prepare for the fact that immediately after the birth of the child it may be necessary surgical intervention, allowing to correct the detected malformations. At the same time, remember that the doctor has the right to offer one or another variant of pregnancy management, and in any case, the final decision is made by the family.