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Prenatal screening and prenatal diagnosis. What is free estriol? Passage of screening and reliability of results

During pregnancy, a woman's doctor prescribes many different tests and procedures, including prenatal screening (PS).

IN general case prenatal screening is a set of studies aimed at detecting fetal diseases. Thanks to screening, the child, while still in the womb, can be examined for a number of serious illnesses, which will not only prepare the mother for his future condition, but also help prevent a number of problems.

What is prenatal screening

Produced studies are easy to conduct and safe for mom and baby, so they are assigned to all pregnant women.

The prenatal screening program includes:

  • Ultrasound (ultrasound),
  • biochemical screening (blood test for markers).

Prenatal screening does not provide a specific diagnosis.

It only makes it possible to determine the likelihood of a particular pathology and identify women with specific risks.

To make a diagnosis, additional studies are required, such as consultation with specialists and invasive diagnostics.

Disease Risk Check

Screening can detect markers of diseases such as:

  • Down Syndrome,
  • Edwards Syndrome,
  • turner syndrome,
  • Smith Lemli Opitz Syndrome,
  • patau syndrome,
  • Cornelia de Lange syndrome
  • defect neural tube,
  • triploidy.

Basic risks

Every pregnant woman is at risk of chromosomal abnormalities. In this regard, biochemical screening can be carried out at will and is recommended for any pregnant woman, but in without fail appointed in the presence of certain indications. Among them:

  • age over 35 years old,
  • multiple pregnancy,
  • spontaneous miscarriages,
  • the birth of a child with a congenital pathology,
  • hereditary diseases,
  • the threat of miscarriage in the early stages,
  • viral infections in the early stages,
  • taking medication early
  • mother's alcohol or drug addiction,
  • increased levels of harmfulness at work and at home,
  • conception from a close relative.

Baseline risk is determined prior to screening and depends on gestational age and age future mother. It is also called original.

Research results (individual risk) are presented as a ratio of two numbers. For example, 1:1415. This relation means that one out of 1415 pregnant women with similar baseline results has a baby with the disorder she was tested for.

Factors affecting the result

As mentioned earlier, there are some factors that can affect screening results and should be taken into account during the procedure. These include:

  • race (in the Negroid, AFP and hCG are higher than in the European),
  • body weight (with big weight women are higher and vice versa),
  • IVF application,
  • multiple pregnancy (indicators will be overestimated, it is not advisable to carry out, since one of the fetuses may have diseases, and the second will be healthy),
  • the possibility of miscarriage (recommended to postpone),
  • diabetes,
  • colds and other similar diseases,
  • bad habits
  • human factor (for example, the doctor indicated the wrong term in the direction).

Effectiveness of prenatal screening

The effectiveness of screening directly depends on the health of the pregnant woman and the factors that have just been discussed.

Any minor illness and even ordinary stress can lead to a change in the composition of the blood, so doctors recommend taking tests only in good health and a relaxed state.

The quality of the tests carried out, as well as their methodical nature, that is, strict adherence to the above scheme in compliance with the terms of pregnancy, is also important.

When undergoing screening, it should be remembered that these methods can only detect some genetic diseases.

Having successfully passed the test with obtaining normal results, a woman cannot be 100% sure that her baby will not have other congenital diseases.

At the same time, positive results also do not guarantee that the child will be born with pathologies. A woman must weigh all the pros and cons herself, making a decision about the future fate of her fetus.

False negative result

The situation is reversed with false negative results when the mother of the unborn child received good results after passing the tests, but the baby was born with pathologies. Such cases in Once again prove the exemplary nature of the research.

False positive result

The situation when the child was diagnosed high probability chromosome defects, but he was born without them, means that the result was a false positive. This scenario could lead to additional surveys child after birth. For a mother, such a turn becomes a real happiness.

Prenatal screening 1st trimester

For a period of 10-13 weeks, the doctor should prescribe the first screening for a pregnant woman. It includes 2 safe procedures: Ultrasound and blood donation for a special test.

First screening ultrasound

The first ultrasound allows you to identify gross defects that have arisen during the development of the fetus. Among them, anencephaly, cervical hygroma, omphalocele and other specific anomalies may occur. During the examination, the doctor checks the viability of the embryos, their number, and also sets a more accurate gestational age.

Collar space thickness (TVP) becomes the main indicator of genetic diseases. To determine it, the width of the layer of subcutaneous fluid on the back of the child's neck is measured. Fine this indicator does not exceed 2.7 mm. If the value of TVP is higher, then the risks increase significantly.

In addition to TVP, the doctor examines nasal bone, which is present and clearly visualized in a fetus without chromosomal abnormalities, and examines for the presence of congenital malformations. Those data that are outside the norm are called disease markers. The more of them were found, the higher the likelihood of genetic abnormalities.

However, the appearance of only one of them is not the reason for the diagnosis.

"Double Test"

Biochemical screening in the first trimester is limited by rigid time frames. If you donate blood a little earlier or later, then its accuracy will drop sharply, so you need to know exactly the gestational age.

Counting the menstrual cycle does not always give the correct result, especially if it was irregular or if the pregnancy occurred immediately after childbirth. Given this factor, a double test is prescribed by a doctor after an ultrasound scan, where exactly the number of weeks of pregnancy will be determined.

The "double test" is an analysis to determine the level of specific placental proteins in the blood. Specifically, the content of two proteins is detected (hence the name of the test):

  • β - hCG - free beta subunit chorionic gonadotropin human,
  • PAPP-A - protein of pregnancy (Pregnancy-associated Plasma Protein-A).

Blood is taken from a pregnant woman from a vein, in the morning on an empty stomach. Normal hCG value depends on the equipment on which the blood test was performed. They are always indicated in the results of the analysis so that they can be adequately evaluated. The average value of the hCG level among women with the same period is indicated by the median. And the ratio of the hCG level to the median is designated MoM (multiple of median). Permissible fluctuations of this indicator are 0.5-2.

For more information on what is MoM, read

When the level of these proteins deviates from the norm, there is high risk the presence of chromosomal and some non-chromosomal defects in the fetus. If the deviations are serious, then the pregnant woman is sent to genetics. In other cases (with small deviations), doctors recommend not to panic, but to wait for the second screening, which will clarify the situation.

Read more about the norm and deviations from the norm of the level of hCG, read

An analysis of the protein level of pregnant women is also carried out with an indication of the normal values ​​​​and the actual value of the expectant mother.

An increase in the concentration of PAPP-A is not as dangerous as a decrease. This protein may be elevated due to multiple pregnancy, low location placenta or even with severe toxicosis. A decrease indicates congenital pathologies in the fetus or diseases in the mother. Deviations from the norm require a doctor's consultation, as each case is individual.

Read more about normal and abnormal levels of PAPP-A, read

Prenatal screening II trimester

Unlike the first trimester, screening for the second period of pregnancy begins with a blood test, after which an ultrasound is performed.

"Triple Test"

At a period of 16-18 weeks, blood is taken from a pregnant woman again from a vein and analyzed, but in this case indicators will be different than at the first screening. The "triple test" makes it more likely to identify malformations of the neural tube of the fetus. Less accurate results are obtained by a test for detecting Down syndrome and Edwards syndrome (70%).

The second biochemical screening determines the concentration of the following blood components of a pregnant woman:

  • AFP - alpha-fetoprotein(fetal protein that is excreted by the kidneys and enters the mother's blood),
  • E3 - free estriol (synthesized in the placenta).

If there are any abnormalities in the development of the fetus or in its chromosomal correspondence, the levels of these proteins will differ from the norm.

In some cases, the “triple test” can be supplemented by the detection of another indicator of inhibin A (the hormone that the placenta produces), then it will be called the “quadruple test”. Determination of the concentration of inhibin may be required when it is necessary to clarify the results of the first screening, if they revealed large deviations from the norm. However, this test is not available in all clinics.

More about the norm and deviations from the norm AFP levels, read

Read more about the norm and deviations from the norm of the level of free estriol - E3, chiatite

Read more about the normal and abnormal levels of inhibin A, read

As in the case of the first screening, the obtained levels are compared with normal values, which makes it possible to detect deviation. The risk calculation is carried out in a specially designed computer program, the results of which are analyzed by the doctor.

The results obtained are correlated with the indicators of the first screening, and a conclusion is made only from the complex of all indicators.

Second screening ultrasound

The second mandatory ultrasound is prescribed by the doctor at 20-24 weeks. This screening allows to identify with sufficient accuracy the anatomical anomalies of the fetus, such as defects of the spinal cord and brain, heart, gastrointestinal a path, defects of development of extremities, facial crevices and other deviations.

If these deviations are detected, doctors cannot carry out surgery after childbirth, therefore they are an indication for interruption of gestation or put the mother in front of the fact that her child will be different from other children.

In addition, markers of chromosomal pathologies are evaluated at this stage, among which there may be growth retardation, shortening tubular bones, pyelectasis, cysts in the brain and much more.

Prenatal screening III trimester

The period closest to childbirth is accompanied by the passage of the third mandatory screening. At a period of 30-32 weeks, a woman needs to undergo another ultrasound.

With an ultrasound examination, the doctor will be able to assess those anatomical features that could not be seen before. These include narrowing urinary tract, some heart defects, hydrocephalus. If they are found, they are subject to correction. surgically already after childbirth.

In addition to ultrasound with an examination of the structural features of the child, a pregnant woman is also prescribed dopplerometry, during which the doctor examines the blood flow in the baby's vessels, the woman's uterus and the umbilical cord that connects them. When violations with blood flow are detected, a treatment course is prescribed, which the doctor usually recommends taking in the maternity hospital in the wards for being before childbirth, that is, “lie down on preservation”.

How to calculate risks

In our country, the calculation of risks is mainly carried out using one of the following computer systems:

  • DELFIA-Life Cycle

The system allows you to calculate the probability of such pathologies as trisomy on chromosome 21 (Down syndrome), on chromosome 18 (Edwards syndrome), on chromosome 13 (Patau syndrome), on the X chromosome (Syndrome Shereshevsky-Turner), triploidy, defects of the central nervous system. The program takes into account the individual data of the pregnant woman and the factors influencing the detection of deviations. Individual indicators include the results of ultrasound in the first trimester.

  • PRISCA - Prenatal Risk Assessment

The program identifies the risks of trimosomy on chromosome 21 (Down syndrome), on chromosome 18 (Edwards syndrome) and neural tube defects. The patient's baseline and factors that may affect the final result are also taken into account.

  • "Isis"

Complex "Isida" also performs the calculation of similar PRISCA risks. This takes into account almost all the factors that can give false positive result: ethnic group, the presence of chromosome disorders in a child born earlier, and others. The advantage of the product is compatibility with automatic ELISA analyzer Alisei, from where he takes part of the data.

The difference between one system and another lies in the range of risks assessed. The effectiveness of each of the methods is almost the same. In addition to these programs, there are other less common developments.

If the results are positive

If as a result of the analyzes a risk level of more than 1:380 was obtained, then it is considered high and may require a more detailed examination.

The main thing to avoid in similar situation- it's panic.

Only a calm attitude will help to avoid breakdowns and give real results in further research.

Further research may include the following items:

  • genetic counseling,
  • repeated ultrasound (recommended by another specialist and with more modern equipment),
  • invasive study (analysis amniotic fluid, chorionic villus sampling, cordocentesis).

Repeating the "double" or "triple test" is not recommended.

Re-study

Repeated ultrasound can be prescribed in the case when the indicators biochemical screening were normal, but ultrasound revealed some external abnormalities. The reason for this phenomenon may be the use of outdated equipment and the human factor. A re-examination will help confirm or refute the presence of such deviations.

genetics consultation

A geneticist is not a gynecologist. He is well versed in chromosomal disorders and can, by a simple conversation with a pregnant woman, find out whether she is prone to genetic diseases. To do this, the doctor interrogates the patient for the presence of any serious diseases among relatives, carefully examines the tests and markers found.

Not all markers are indicators of genetic abnormalities.

There are basic and indirect indicators by which the risk is determined.

For example, if salt deposits are found in the heart of a child, then this is not a sign of pathology. In the future, they will simply turn into chords or disappear. But this marker is a confirmation of the high risk of Down's syndrome if it is found along with the pathology of the nasal bone and abnormal thickness of the collar space.

In any case, a consultation with a geneticist will allow you to get a qualified answer to the situation with the analyzes.

Invasive research

If the risk genetic disease turned out to be high, then it is possible to resort to less sparing studies. Invasive methods include 3 types of research:

chorion biopsy,

Amniocentesis,

Cordocentesis.

  • The safest is amniocentesis(analysis of amniotic fluid).

It can be carried out at 16-20 weeks of pregnancy. During the procedure, the doctor makes a puncture of the amniotic membrane and takes a small amount of amniotic fluid for laboratory testing. Actions are carried out under ultrasound control, bypassing the placenta. A free pocket is used to insert the needle. If free space no, then the thinnest part of the placenta is used. After the procedure, complications are possible in the form of leakage or premature withdrawal of water, detachment membranes and the development of alloimmune cytopenia in the fetus.

  • Parallel to amniocentesis for a period not earlier than 18 weeks can be performed cordocentesis.

Cordocentesis is the collection and examination of blood from the umbilical cord of the fetus. The analysis requires at least 5 ml of blood. In addition to genetic diseases, it allows you to determine the severity of the Rh conflict, if any, and, if necessary, perform a blood transfusion.

  • Chorionic biopsy consists in the analysis of chorionic villi, which are obtained by sampling chorionic tissue through the wall of the uterus.

Chorionic biopsy is performed for a period of 10-12 weeks. At least 5 mg of tissue will be required for analysis for genetic diseases. If at the first attempt the doctor failed to get it in enough, then it can be retaken. The third attempt can adversely affect the course of pregnancy, significantly increasing the risk of miscarriage.

An invasive study is a full-fledged operation, therefore it is prescribed only in cases of high risks congenital pathologies, as it can cause miscarriage, infection of the fetus, the development of Rhesus conflict and other complications.

Conclusion

The passage of prenatal screening procedures is recommended for all pregnant women without exception, but doctors do not have the right to impose their opinion, therefore, the woman herself makes the decision to take tests and ultrasound examination. Women who fall into special group risk for any indication, screening is mandatory.

Based on the screening results, doctors cannot make a diagnosis. They can only identify certain risks in a pregnant woman.

And a positive result of the presence of markers is not always accurate, and in those women in whom they were found, it may well be born healthy baby. Conversely, Down syndrome and other chromosomal abnormalities may not show up during screening. But although these studies are exemplary, they allow a woman to mentally prepare for possible problems with the health of your child.

Pregnant women should be aware of perinatal screening

First you need to define what p means. prenatal screening. English word Screening is translated as "sift". Doctors do screening examinations in order to immediately distinguish a small group from a large mass of people that has a high percentage of the risk of some kind of pathology. Screening is especially important for pregnant women to identify those who may have a child with a birth defect.

Now it is desirable to perinatal screening for such birth defects fetus:

  • Edwards syndrome (changes in the 18th pair of chromosomes);
  • Down syndrome (changes in the 21st pair of chromosomes);
  • abnormal development of the neural tube (anencephaly and spina bifida).

The main word here is “Risk”. Statistics say that Down syndrome occurs in 1 out of 700 births. Edwards syndrome occurs in 1 in 7,000 newborns. Spina bifida happens - 1-2 babies per 1000 births.

No pregnant woman is immune from the birth of a child with a genetic pathology. The risk increases significantly when a woman is over 35 years old, or her relatives had children with defects.

What is screening and why is it needed?

Screening is a method of examination to find out the percentage of risk that a child will be sick. Now let's clarify how screening is done:

Carried out very precise combined screening, necessarily, with the processing of information on a computer. In every separate case the risk is calculated.

Those who are at high risk will have to do a more accurate examination - an amniocentesis or a chorionic villus biopsy is performed. This means that without any danger they will take the cells of the fetus and the geneticist will determine the chromosome set. The examination will show whether there are chromosomal abnormalities or not.

When the diagnosis of a genetic disease is confirmed, the couple is offered an abortion because the genetic changes cannot be treated.

In cases where, after screening, a large percentage of the risk of a genetic defect in the fetus is found, they are sent to do an invasive diagnosis in order to find out for sure whether there are chromosomal abnormalities or not. Only doctors always warn that this survey can provoke an abortion - you need to be prepared for this.

How is screening done?

Perinatal screenings do during the 1st and 2nd trimesters of pregnancy, but for each period they use their own biochemical markers. The process will be like this:

Ultrasound is done after the 11th week of pregnancy by a specially trained doctor. In these terms, you can already notice obvious malformations:

  • the diagnosis of omphalocele is made;
  • anencephaly is detected;
  • defects of the heart and blood vessels are determined;

Now, even in the 1st trimester, it is possible to determine Down syndrome by ultrasound.

2. It is necessary to donate blood.

Perinatal screening includes everything key surveys fetus during the mother's pregnancy. This is one of the few methods that allows you to establish the risk of developing Down syndrome, Edwards syndrome, Patau syndrome, triploidy, neural tube defects, etc. in the early stages of pregnancy.

Ultrasound 3D, 4D on a new device from 2000 rubles. CD as a gift!

What is perinatal screening

Perinatal screening is a set of diagnostic measures that allow prenatal examination of the fetus and identify expectant mothers with increased risk congenital pathologies and developmental disorders of the child. This screening is recognized in many countries as the basic test that gives the most full information specialist in charge of pregnancy, and future parents, regarding the health of the baby.

Many women, speaking about this examination, often confuse two concepts - prenatal and perinatal. So here it is prenatal diagnosis is carried out before conception, i.e. in this case, the expectant mother is examined. Doctors use different methods to determine the risks of having a sick child. Perinatal screening is an examination during pregnancy and the object of study in this case is the fetus. The importance of such a study, especially on early stages, undeniable: in the patient, if the screening showed disappointing results, always there is a choice - to continue pregnancy or to interrupt.

Stages of perinatal screening

The whole complex of activities within the framework of perinatal research is divided into three stages, each of which a woman must undergo at a certain stage of pregnancy. The first part of the diagnostic procedures falls on the gestational age of 11-13 weeks, the second time you need to go for diagnostics after reaching 18-24 weeks, the third perinatal screening is carried outat 30-34 weeks of gestation. The first 2 stages consist of two basic diagnostic procedures, each of which helps to identify genetic abnormalities

  1. gives the most complete picture regarding the structure of organs, the work of the heart, as well as the external signs of the baby and his position in space.
  2. Biochemical blood test - this analysis is aimed at identifying certain substances in the patient's blood, of a protein nature, which are produced by the fetus and amniotic membranes and may indicate the presence of chromosomal pathologies and disorders in the formation of the neural tube.

In our medical center, fetal examination is carried out on a modern

I stage of perinatal screening (11-13 weeks)

Examination of the future mother during this period allows you to get a huge amount of information regarding the condition of the baby and the general course of pregnancy. Ultrasound examination at a period of 11-13 weeks of pregnancy in modern clinics is carried out by the method of three-dimensional echography - thereby obtaining the following data regarding pregnancy:

  • The number of viable embryos implanted in the uterus.
  • Definition exact date pregnancy.
  • The presence or absence of gross malformations.
  • The thickness of the nuchal space of the TVP (used as an indicator of some chromosomal syndromes).
  • Visualization of the nasal bone is important to exclude the possibility of Down syndrome.

After undergoing a classic ultrasound, a pregnant woman takes biochemical analysis blood, which at this stage is called the “double test”, due to the fact that the quantitative levels of two protein components are measured: PAPPA and hCG (free β subunit).

hCG (human chorionic gonadotropin) - one of the main pregnancy hormones contained in the mother's blood serum. Its low level indicates placental pathologies, A increased content may indicate a chromosomal abnormality in the fetus.

PAPP-A - also called protein A . Its concentration in maternal blood may indicate the presence of chromosomal diseases such as Down and Edwards syndromes.

Stage I I perinatal screening (16-18 weeks)

At this stage, it is quite possible to conduct 3D or 4D ultrasound, which make it possible to evaluate all the external aspects of the baby, and also, in the case of four-dimensional echography, determine the mobility of the fetus and its gender.

The biochemical component of the second stage is a "triple" test, which involves the identification and measurement of the following protein components in the blood of the expectant mother:

  • Free β subunits of hCG.
  • Free estradiol.

ACE (Alpha-fetoprotein) - a specific protein that is produced directly by the fetus and enters the mother's blood through the placenta. Its high content may indicate defects in the neural tube of the fetus and defects in other vital organs. A decrease in ACE can be detected with chromosomal diseases such as Down syndrome.

Free estradiol - female steroid hormone, which during pregnancy should be produced by the placenta. A decrease in the level of estradiol in the blood of a woman may indicate a violation of the development of the fetus.

Results of perinatal screening

Despite the fact that perinatal genetic screening is recommended for all pregnant women, there are a number of families for which a thorough diagnosis and consultation with a geneticist during pregnancy is mandatory:

  • The spouses have relatives with severe genetic diseases.
  • In consanguineous marriage.
  • At late pregnancy(mother over 35 and father over 40);
  • If the couple has already had cases of the birth of children with impaired genetics.
  • If the mother has severe somatic diseases (pathologies of the heart or kidneys, diabetes mellitus);
  • In severe pregnancy;
  • If you suspect the presence of genetic pathologies identified during ultrasound.

Evaluation of results

Data ultrasound diagnostics and blood biochemistry are evaluated together, using special programs, which makes it possible to establish the individual risk of a woman. The risk group includes expectant mothers, whose results are 1:300 - the risk of having a baby with a chromosomal abnormality. However, it should be understood that this result is not yet a diagnosis. To establish more accurate results, the pregnant woman is heading for additional research as an invasive diagnostic. And now let's take a closer look at the most important part of perinatal screening during pregnancy - ultrasound.

The role of 3D ultrasound in perinatal screening: 3D or 2D?

To date, no one doubts that the methods of ultrasound diagnostics - the most important aspect control prenatal development, age and position of the fetus. At the same time, the technical base of medicine does not stand still, and in addition to the classic, two-dimensional ultrasound, such a useful diagnostic practice as 3D ultrasound or three-dimensional echography has come in all respects. The advantages of this method of research are the possibility of obtaining a three-dimensional image, which in all colors demonstrates to the specialist and future parents, all aspects of the external manifestations and organs of the baby.

Differences between 3D ultrasound and classical ultrasound

All ultrasonic research methods have general principle, which is based on the use of ultrasonic radiation, the wave frequency of which does not exceed 20 kHz. The supply of such a wave load in a pulsed mode makes it possible to assess the functional normality and morphological structure of tissues, organs and systems of the fetus. At the same time, the traditional two-dimensional method displays a flat image on the dashboard monitor, which is understandable to doctors, but does not have information content for non-professionals, namely, for the child's parents, who are looking forward to the first acquaintance with the baby. At the same time, it should be noted that this method of diagnostic control is important for medical specialists conducting pregnancy, as it makes it possible to fully assess the structure of the internal organs of the fetus, which is incredibly important when organizing complex control.

Three-dimensional echography produces a full-fledged three-dimensional image that does not require decoding and clearly reflects the external features and position of the baby in the womb.

Advantages of 3D ultrasound in perinatal screening

3D ultrasound provides physicians with a number of obvious advantages:

  • Clearer picturemakes it possible to establish a number of defects that cannot be detected during classical ultrasound screening: anomalies of the hands, cleft face, skeletal malformations, violations of the formation of the anterior abdominal wall, anomalies of the placenta, features of the structure of the external genital organs, non-closure spinal cord etc. The identification of all these deviations requires a change in the strategy for managing such a pregnancy.
  • 3D ultrasound allows you to determine the sex of the babymore precisely in the early stages of pregnancy, which may be necessary not only to satisfy the curiosity of future parents, but also in terms of eliminating the possibility hereditary pathologies associated with gender.
  • Psychological readiness of mother and fatherto the birth of a long-awaited child, of course, increases after the initial acquaintance with the baby, even if through a monitor and a photograph, which, at the request of the parents, can be provided after passing this manipulation.

Features of 3D echography

According to the results of numerous medical research, 3D ultrasound absolutely safe way diagnostics, which is used for medical indications. The following factors can be attributed to the features of 3D ultrasound during screenings during pregnancy:

  • The most informative three-dimensional echography at the period of 22-33 weeks of pregnancy, since during this period the external signs of the fetus are already sufficiently formed, and its dimensions do not interfere with visual review.
  • Duration 3D ultrasound is about 40 minutes, which is much longer than the time required for a classic two-dimensional screening.
  • The bladder does not have to be full before the 3D ultrasound.
  • The diagnostic capabilities of the technique decrease significantly in the presence of such features of the patient or the course of pregnancy as severe obesity of the expectant mother, oligohydramnios, the presence of scars on the abdominal wall of the woman, awkward position fetus.

Three-dimensional echography is a diagnostic practice that has earned the trust of doctors and patients around the world, confirming its exceptional efficiency and safety, both for a woman and for a baby. At the same time, today, it is 3D ultrasound that remains the “gold standard” for intrauterine study of the structure of facial structures, limbs, sexual characteristics and volumetric formations in the fetus, as well as a backup method for detecting such chromosomal anomalies as Down syndrome, Patau, etc.

The value of 4D ultrasound in perinatal diagnostics: advantages and features

In modern practice of medical management of pregnancy, such a procedure as 4D ultrasound has become basic, both for a specialist who controls the course of gestation, and for impatient parents who are waiting to meet their child. This technique has several significant advantages over the classical two-dimensional screening and is very often used as an addition to base rate mandatory research.

4D ultrasound will provide an opportunity not only to fully assess the health and development of the baby, but also give parents the joy of the first visual contact with the child, who at the same time will stay in the natural intrauterine environment.

4D ultrasound - features and benefits

Somewhat extended in comparison with the usual two-dimensional echography. This is ensured by the fact that the examination (also called color ultrasound) allows you to evaluate the external manifestations of the fetus, using four measurements simultaneously: depth, height, length and time. As a result of the procedure, the image displayed on the dashboard monitor will resemble a video clip that demonstrates in real time not only the appearance and main morphological features of the baby, but also his movements, facial expressions, gestures and smile.

If the baby has not turned his back to the ultrasound scanner, such a spectacle causes a lot of positive emotions from parents and provides certain diagnostic information to a specialist.

Positive aspects of 4D ultrasound for a pregnancy specialist

In addition to the data standard for all ultrasound methods, regarding the age, size and position of the fetus, 4D ultrasound gives the specialist the opportunity to determine the presence of the following anomalies in the development of the baby:

  • Facial defects (cleft face)
  • Skeletal malformations (non-overgrowth of the spinal cord)
  • Anomalies of the hands (quantitative pathologies of the fingers)
  • The presence of volumetric formations in the fetus
  • Pathological changes in the placenta
  • Anterior abdominal wall defects
  • Abnormal development of the external genitalia

4D ultrasound makes it possible to track the natural movements of the fetus. This can also become important information in the process of confirming one or another developmental pathology. Thanks to the extended view that this ultrasound screening option offers, it is also possible to visually assess the structure of all external signs. This is especially true for facial structures (nasolabial triangle, lips, ears, chin, nose, etc.).

It should also be noted that the 4D technique provides more accurate information regarding the gender of the baby. This information is of interest to the doctor due to the presence of a hereditary factor of pathology or genetic abnormalities linked to sex. And this is one of the main tasks of perinatal screening.

Positive aspects of 4D ultrasound for future parents:

  • Opportunity to see the baby long before his birth, establish a certain psychological contact with him, and also prepare for the external features of the crumbs.
  • You can accurately determine the gender and even see the confirmation personally, on the monitor screen. This aspect almost always worries parents, as well as the developmental features of the child.
  • Parents can get the video , which will remain unusual memory about such important period in the life of every family, like pregnancy. We give a CD with a record as a gift!

How is 4D ultrasound performed?

The method of carrying out the procedure is practically no different from the standard one. However, a 4D ultrasound takes almost three times as long as a black and white ultrasound (about 45 minutes). At the same time, a pregnant woman should know that filling Bladder does not affect the results. In addition, it should be understood that the 4D technique has the maximum level of information in the period from 22 to 33 weeks, which is due to the development and size of the fetus.

Patients suffering from severe forms of obesity or having scars on the abdomen, as well as when diagnosing a condition such as oligohydramnios, should be prepared for the fact that the picture may not be clear enough. In almost all other cases, 4D ultrasound will become beautiful way get to know the baby and get a guarantee of its normal intrauterine development. Clinic Diana offers its patients a 4D ultrasound procedure, guaranteeing the information content and safety of the baby and the expectant mother.

Analysis for hCG β - unit in perinatal diagnosis

HCG (chorionic gonadotropin) is a hormone whose concentration increases dramatically during pregnancy. Its increase indicates the conception that has occurred, which is extremely important during pregnancy resulting from infertility treatment. HCG is not strictly a "female" hormone. This substance is specially administered to men in order to improve spermogram parameters in cases of suspected male infertility.

What is hCG and β-hCG

This substance consists of two components:

  • α-unit, similar to other hormones;
  • β - a unit - unique to hCG, distinguishing it from other hormonal substances.

That is why it is precisely β - unit that is analyzed, and the analysis itself is often called β - hCG.

The hormone is produced by cells of the germinal membrane to stimulate the hormones that support pregnancy - progesterone and estrogen. This prevents the onset of menstruation and allows the embryo to “take root”. That is why in case of infertility, doctors analyze hCG level in the patient's body. If its content falls or falls behind the norm, a woman is prescribed hormonal preparations supporting pregnancy. It is necessary to monitor the level of the hormone in women prone to habitual miscarriage and having missed abortions.

The concentration of hCG increases rapidly until the placenta is formed, which later takes over the hormonal function. The rapid increase in the level of the hormone indicates that the pregnancy has been preserved and the embryo is developing. In the future, the content of the hormone decreases, remaining elevated before childbirth and some after them.

The normal content of hCG in different women varies greatly. The doctor determines whether everything is normal, according to the dynamics of the change in the indicator in a particular patient.

Approximate indicators of the concentration of the hormone during pregnancy are shown in the table

Deadline, weeks Concentration, honey/ml
1 20-155
2 100-4850
3-4 Up to 82,000
5-6 Up to 151,000
7-8 Up to 230,000
9-10 Up to 290,000
11-16 Reduced from 290,000 to 245,000 or less
17-25 Decreases to 50,000-80,000
25-37 gradually decreases to 40,000 or less

Level Mismatch hcg due date observed in pathologies of pregnancy and abnormal development of the fetus

Unlike pregnancy, in diseases that cause an increase in hCG levels (ovarian, stomach and breast cancer), the level of the hormone rises gradually and does not decrease. Therefore, a woman several times during pregnancy, how many times such an analysis is prescribed

How is the β-hCG screening assay performed?

For this study, blood is taken from a vein or urine, but the hormone in urine is determined later, and the result is not so accurate. Therefore, it is better to rely on a blood test showing the presence of the hormone and its concentration.

The material is taken in the morning on an empty stomach, if you need to take tests urgently, you need to starve for 4-6 hours. It is advisable not to take at this time medicines. If the level of hCG in the early stages began to rapidly decrease or increase, you need to consult a doctor and identify the cause.

Where to do perinatal screening in St. Petersburg

SPB offers all stages of perinatal screening, guaranteeing individual approach to every woman and maximum reliability the results obtained. Our specialists have vast experience in the field of diagnostics during pregnancy. Hardware medical center makes it possible to carry out both basic and additional stages of screening.

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

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There is a specific list laboratory research that all pregnant women should go through. Prenatal screening not mandatory for everyone, but only for those women who are in a special risk group for congenital anomalies.

So, screening should be done in such cases:

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

Screening studies are carried out in each trimester. Highest value has research in the first and second trimesters.

1st trimester screening

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

Screening in the first trimester includes:

  • fetal ultrasound;
  • Biochemical study of blood.

Fetal ultrasound in the first trimester

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

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

  • Incorrectly calculated gestational age;
  • Developmental disorders of the fetus as a result of hormonal, infectious diseases mothers;
  • The presence of a genetic pathology;
  • Incorrect position of the fetus, which does not allow to fully measure the distance.

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

The probability of chromosomal abnormalities allows you to determine the study of the thickness of the collar space (NTP). An increase in TPV may signal Down syndrome, Edwards, Turner, Patau.

No less significant in the ultrasound examination of the fetus is the determination of the length of the nasal bone. In the presence of a chromosomal pathology, the formation of the nasal bone is delayed. Accordingly, its absence or small size may signal a chromosomal pathology.

Biochemical blood test

For biochemical research, blood is taken from a vein of a pregnant woman. Blood sampling is carried out on an empty stomach in the morning. Most Interest presents the determination of the levels of human chorionic gonadotropin (hCG), as well as plasma protein (PAPP-A) in the blood of a pregnant woman.

HCG is synthesized by chorion cells. Hormone levels correlate with gestational age.

Chorionic gonadotropin has two fractions: alpha and beta. For the diagnosis of congenital pathology, the determination of the level of beta-hCG is of the greatest importance. Lower hCG normal level observed at ectopic pregnancy, pathology of the placenta, Edwards syndrome. And an increase in hCG may indicate:

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

Determination of plasma protein PAPP-A produced from the 8th week of pregnancy. It is noteworthy that the definition of this indicator after the 14th week is no longer so reliable.

Reduction of PAPP-A in comparison with the normal values ​​characteristic of certain period pregnancy indicate:

  • Chromosomal abnormalities of the fetus;
  • The threat of miscarriage.

It should be noted that an increase in plasma hormone may also indicate the presence of fetal developmental disorders.

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

Pregnant women carry out such studies:

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

Ultrasound of the fetus in the second trimester

The need for ultrasound in the second trimester is dictated by the fact that during this period important functional systems, the study of which will assess the development of the child. Ultrasound helps to study:

  • Proper formation of the spine, limbs;
  • The length of the nasal bone;
  • Dimensions of brain structures;
  • Functioning of internal organs;
  • The main parameters of the child;
  • The size and structure of the placenta;
  • The size of the cervix;
  • Amniotic fluid level;
  • fetal heart rate;
  • The length of the umbilical cord;
  • The condition of the appendages of a pregnant woman.

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

Not less than important role the location of the umbilical cord also plays, normally it is attached to the central region of the placenta. There are other atypical options for placing the umbilical cord: marginal, sheath, split. Such anomalies can lead to difficulties during childbirth, in particular, to the freezing of the fetus.

The umbilical cord has three vessels: two arteries and a vein. If at least one artery is missing, this can lead to a violation of the formation and development of the internal organs of the child.

During an ultrasound examination, the doctor can calculate the level of amniotic fluid. What can this indicator say? With oligohydramnios, there is a risk of forming a defect in the limbs, spine, and organs of the nervous system.

Biochemical blood test

Estriol is a hormone responsible for the formation of the placenta. High level of this hormone can be determined during multiple pregnancy, as well as with a large weight of the fetus. A low level can inform about placental insufficiency, the threat of miscarriage, hypoplasia.

Alpha-fetoprotein (AFP) is a protein synthesized by the fetal liver. The substance enters the mother's body through the placenta, due to which it becomes possible definition its concentration by examining the venous blood of a pregnant woman.

A low ACE level is observed when:

  • Down syndrome;
  • Edwards syndrome;
  • Vesical skid;
  • Fetal death.

A high concentration of alpha-fetoprotein may indicate:

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

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

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

A chorionic villus biopsy also reveals chromosomal pathologies and genetic diseases.

Remember: the doctor makes a conclusion about the risk of having a baby with a pathology based on the results of all screening studies. Having received an unsatisfactory result in your hands, in no case should you panic. The doctor will recommend to undergo additional studies, the results of which can refute all worries about the child's health.

Grigorova Valeria, medical commentator

Perinatal screening is special complex, which is recommended for almost all pregnant women on early term. This study is carried out to completely exclude possible fetal anomalies that have arisen due to a chromosomal or gene disorder. These birth defects are often untreatable, which is why it is so important to ultrasound treatment at an early date. The term "screening" in translation means "sifting".

Screening of newborns for hereditary diseases consists of a triple ultrasound examination and a biochemical blood test. There is no need to be afraid of this procedure, it is completely safe for both the mother and the baby.

Doctors recommend perinatal screening in the first trimester, between 10 and 14 weeks, with the optimal period being from 11 to 13 weeks. The study helps to assess the course of pregnancy according to all the required parameters, the fact of the development of multiple pregnancy. However, the main purpose of ultrasound at this time is to determine the thickness of the collar space of the embryo. By itself collar space is an area of ​​fluid accumulation between soft tissues neck area. In the event that the obtained value exceeds the permissible norm, a risk is likely genetic anomaly in fetal development.

Only by ultrasound it is impossible to draw a conclusion, a whole range of studies is needed, which are included in the perinatal. Only on the basis of a comprehensive study can conclusions be drawn. In general, a biochemical blood test is also called " double test”, and make it for a period of 10-13 weeks. During this study, the level of two placental proteins is examined in the woman's blood.

Based on the results of an ultrasound examination, a calculation of a possible genetic risk, and also after obtaining data on the protein level, a risk calculation is carried out using computer program. Such a specialized program allows you to take into account even such factors as ethnicity women, her age, weight. Also, the calculation takes into account the fact of the presence of hereditary diseases in the family and family, the presence of various chronic diseases. After a comprehensive study, the doctor examines the results and is able to attribute pregnancy to a risk group, such as Edwards syndrome and However, even in this case, such a threat is not a diagnosis, but only suggests a possibility. Only an experienced geneticist can accurately determine, who will prescribe a further examination. This procedure is more complicated, in abdominal wall an instrument is inserted and a part of the chorion is taken away. Such a biopsy is more dangerous because it can lead to some complications.

Perinatal screening should be done exactly at this time, since the accuracy of the result is maximum during this period. In the case when the tests are given too late or too early, the accuracy of the result is reduced several times. If a woman has an irregular menstrual cycle, then thanks to ultrasound you can accurately determine the gestational age. The next such examination must be carried out for more than late term, approximately 16-18 weeks.

The first perinatal screening is a very exciting and touching event. A woman will meet her baby for the first time, see his arms, legs, face. From the usual medical examination it turns into real holiday for mom and dad baby. The main thing to remember is that any deviations from the norm are simply referred to as a risk group, and not a diagnosis. In this case, you do not need to be upset, it is better to just conduct an additional examination.