Medicine today 

perinatal screening. What is free estriol? What is hCG and β-hCG

To monitor his condition of the unborn child, every month a woman takes several basic tests: general analysis blood and urine. In addition to them, several times during the entire pregnancy, doctors recommend taking prenatal screening. What is this survey? What can its results say?

Research features

Prenatal screening is an examination that takes place between 10 and 14 weeks (first trimester). According to special indications, it is recommended to do it in the second, and even in the third trimesters. The examination shows what is the probability that there are violations in the development of the fetus. Usually it is carried out in two stages: a study of blood taken from a vein and an ultrasound. After carefully reviewing the results, the geneticist will assess the risks. Screening can be done by all pregnant women if desired.

But there are situations in which women need to go through it:

  1. If the future parents are relatives.
  2. There have been miscarriages or induced abortions before the current pregnancy.
  3. If intrauterine fetal death has occurred and dead birth child.
  4. If a woman has had a viral disease.
  5. There are those in the family who suffer from genetic diseases.
  6. The family already has children with Down syndrome or other similar disorders.
  7. Prohibited drugs were used during treatment.
  8. Pregnant 35 years or more.
  9. Parents want to be sure that their child is doing well.

What will the doctor pay attention to? First of all, he will look at the size of the embryo. This parameter is called KTR (coccygeal-parietal size). Also evaluate the circumference of his head and the distance from the forehead to the back of the head. In addition, the specialist will pay attention to other indicators.

  • Are the cerebral hemispheres symmetrical?
  • Have all parts of the brain already developed.

  • In what condition are the bones of the thigh, shoulder, etc.
  • Are the stomach and heart in their place?
  • What are the dimensions of the heart and the vessels leaving it.
  • Belly sizes.

Based on the results of screening, you can see the following violations:

  • failures in development neural tube;
  • syndromes of Patau, Down, Edwards, Smith-Opitts and de Lange;
  • omphalocele (some organs are not inside the body, but outside);
  • triploidy (triple chromosome set).

When is the best time to do the first prenatal screening? Not so much time is allotted for this examination: from the beginning of the tenth to the sixth day of the thirteenth week. Experts recommend choosing a time between these dates.

Assistance in the question of when to do screening should be provided by the attending physician. He, given the date of the last menstruation, will be able to determine exactly what week of pregnancy the woman is in.

How to behave before the examination?

The screening procedure consists of two main parts: an ultrasound and a blood test from a vein.

  1. Ultrasound can be performed in two ways: transvaginally and abdominally. In the first case pre-training no need. In the second, you need to have a filled bladder. Water (at least 0.5 l) will help to achieve this, which must be drunk 30 minutes before the ultrasound.
  2. Before donating blood, you can not eat anything for four hours. And the day before the analysis, you can not eat chocolate and chocolate candies, seafood, meat.

Process Features

As mentioned above, ultrasound is performed in two ways. Each of them has its own nuances.

  1. During a transvaginal examination, a woman needs to free the lower half of her body from clothing and lie down on the couch with her legs slightly bent. The doctor will insert a special probe into the vagina. During the procedure, he will turn it in the right side. These actions will not cause pain or any other discomfort. After this type of ultrasound, discharge with blood may appear.
  2. With an abdominal ultrasound, a woman needs to lie down and open her stomach. The doctor will only move the transducer across the abdomen.

To conduct a blood test, a laboratory assistant will take 10 ml of blood from a vein. It is important to remember that before this it is not recommended to eat.

Decryption

In order to correctly understand the results of screening carried out in the first trimester, you need to know the norms of fetal development. It is also important to know what should happen in the mother's body:

  1. KTR child. By the end of the first trimester, this figure should reach 73 mm.
  2. Value collar space by the 13th week of pregnancy should not exceed 2.7 mm.
  3. Nose bone. According to her condition, the risk of having a child with Down syndrome is estimated. If screening is done at 10-11 weeks, nasal bone rendered. It is not yet possible to determine how long it is. From 12 weeks, the length of the nasal bone should be 3 mm.
  4. Palpitation. Starting from week 10, it will slow down. If at 10 weeks it is about 179 beats per minute, then at 13 - up to 171.
  5. biparental sizes. During the first trimester, the fetus grows from 14 to 26 mm.

An ultrasound scan performed at a period of 10 to 13 weeks will show whether the fetus is developing correctly, whether its size corresponds to the term.

What will the blood test results show?

  1. HCG level. In the normal course of pregnancy, the amount of this hormone decreases by the end of the first trimester. For example, for a period of 10 weeks, its level ranges from 25 to 181 units, and for 14 - from 14 to 114.
  2. How much protein A is in the mother's body. This is a protein that is produced by the placenta. Its amount should increase every week.

The doctor enters all the results of the examination into a computer program. It defines the so-called risks - it is in them that the answers of prenatal screening are deciphered.

In documents, risks are referred to as MoM. In fact, this is a coefficient showing how far the test results are from the norm. Norma Mom - from 0.5 to 2.5. If the indicator is less than 0.5, there is a risk of developing Edwards syndrome, if more than 2.5, there is a risk of Down syndrome.

According to the results genetic research the doctor will determine the likelihood of a particular violation. This value is displayed as a fraction. For example, the record for Down syndrome 1:360 reports that with such indicators, 1 out of 360 children is born with disabilities. According to official data, healthy fetus after the fraction must be a value greater than 380.

At poor screening in the first trimester, MoM will be either less than 0.5 or greater than 2.5. The risk of developing genetic disorders will be displayed as a number after the fraction less than 380.

In case of poor results of prenatal screening, a consultation with a geneticist is indicated. He will plan his next steps.

There are two ways:

  1. Assign the same examination in the second and third trimesters.
  2. Schedule additional research, such as amniotic fluid and placenta. Based on the answers, it will be decided whether to continue the pregnancy or not.

What can go wrong?

Sometimes prenatal screening in the first trimester can be false positive and unreasonably show bad results. This happens for several reasons:

  • If a woman becomes pregnant through IVF. In this case hCG level usually higher, but the amount of protein A is reduced.
  • The pregnant woman is obese. With this violation, the level of hormones increases.
  • Pregnancy with twins, triplets, etc. There are no official norms regarding the amount of hCG, protein A and other indicators.
  • If a woman has a disease such as diabetes. With it, screening shows reduced level hormones. These data cannot be the basis for determining the risks of developing disorders. Diabetes mellitus can cause the examination to be cancelled.
  • Poor results may also occur if an amniocentesis procedure (taking amniotic fluid for analysis) was performed a week before screening.
  • Unpredictably affect the results of analyzes can and psychological condition pregnant. Many women experience great fear and excitement before the examination.

How to identify violations?

How do doctors determine the presence of certain pathologies using ultrasound? They have their own distinctive features:

  1. Down syndrome is characterized by smooth facial features, changes in ductus venosus, a shorter than expected bone of the nose.
  2. With Edwards syndrome, the child has an umbilical hernia, the heartbeat slows down, and the nasal bone is not defined. In addition, the umbilical cord has only one artery.
  3. Patau's syndrome is characterized by an increase in heart rate, misdevelopment brain, slowdown in development and the formation of an umbilical hernia.

Prenatal screening, which is carried out in the first trimester, is a fairly informative examination. With its help, it is possible to identify failures in the development of the fetus. The examination is carried out in two stages: analysis of venous blood and ultrasound. When is the best time to do them? Between 10 and 14 weeks. It is necessary to prepare for screening in advance, for example, by eliminating from the diet harmful products- chocolate, meat and other things that the doctor leading the pregnancy will tell you about.

Perinatal screening is special complex, which is recommended for almost all pregnant women at an early stage. 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 development multiple pregnancy. However, the main purpose of ultrasound at this time is to determine the thickness of the collar space of the embryo. The collar space itself is a zone of fluid accumulation between soft tissues neck area. In the event that the obtained value exceeds the permissible norm, the risk of a genetic abnormality in the development of the fetus is likely.

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 a “double test”, and it is done 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, the calculation of a possible genetic risk, and after obtaining data on the protein level, a risk calculation is carried out using a computer program. Such a specialized program allows you to take into account even such factors as a woman's ethnicity, 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, an instrument is inserted into the abdominal wall and a part of the chorion is taken. 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 completed at a later date, 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.

Complex special surveys, which is recommended to all pregnant women for the timely detection of chromosomal and genetic abnormalities, is prenatal or prenatal screening. This set of examinations includes safe for the child and mother biochemical analyzes blood and ultrasound examinations certain stages pregnancy (during each trimester). Today, screening diagnostics is recommended for absolutely all pregnant women.

What is prenatal diagnosis used for?

A woman has every right to refuse to undergo this set of examinations if she does not want to. Many do not see the point in identifying defects that cannot be treated, especially on later dates(during the II or III trimester). Prenatal screening for trisomies helps women with negative test results to choose between termination of pregnancy and the birth of a child with a chromosomal pathology.

Having received such information in advance, the patient can mentally prepare for the fact that she will have to raise a special baby. If the screening of the first, second and third trimester shows the absence of pathologies, then a woman can calmly, without worries and worries about the health of the child, endure it.

There are specific indications for prenatal screening:

  • age over 35;
  • the presence of such diseases in close relatives;
  • the birth in this family earlier of children with genetic and chromosomal disorders, birth defects development;
  • a history of interrupted pregnancies, where the examination showed the presence of such pathologies in the fetus;
  • various adverse effects on one of the parents shortly before conception (for example, radiation exposure) or the intake of teratogenic drugs by one of them.

Screening gives women the opportunity to prevent or prepare for future difficulties, and for some it helps to reassure that everything is in order. This is especially important for those women who are at risk of having a child with chromosomal disorders. All tests and examinations are absolutely safe for the health of mother and baby.

Characteristics of the most common trisomies

If at the moment of division of the mother's or father's germ cell one or more chromosomes are not separated, then gametes of unequal number of chromosomes are formed. They should contain 23 chromosomes, and with some violations, there are 24 chromosomes. Merging gametes should form one full-fledged cell with a normal set of chromosomes in the amount of 46. When an extra 47 chromosome is added to the cell, they speak of trisomy.

Many deviations in the number of chromosomes are incompatible with life, some of them are rare. Life expectancy depends on the number of physiological disorders affecting important organs and systems. Lagging children with trisomies in mental development can also be different: from moderate to very serious. The most common trisomies are Down syndrome (on the 21st chromosome), Edwards (on the 18th) and Patau (on the 13th). Children with such pathologies survive, but they need the care and help of loved ones.

Diagnosis of trisomy in the first trimester of pregnancy

The first prenatal screening for trisomies is recommended between 10 and 14 weeks of gestation. Most optimal timing during the first trimester is 11–13 weeks. An ultrasound examination is required main goal which is the measurement of the collar space in the fetus. The collar space is called the place in the neck of the child, where fluid accumulates between the soft tissues and the skin. If this value more than normal, then further examination is prescribed to exclude or confirm anatomical anomalies. In addition, the coccyx-parietal size is measured for more exact definition terms of pregnancy.

A biochemical analysis of venous blood at this stage (the so-called "double test") is carried out in order to determine the level of hCG and PAPP-A - specific placental proteins. It should be carried out no later than 1 week after the first ultrasound screening is done during the first trimester (preferably at 11-13 weeks). The content of PAPP-A in the blood during pregnancy is constantly increasing. This substance ensures the normal development and growth of the placenta. An insufficient amount of it in the blood from the 8th to the 14th week of pregnancy may indicate the presence of abnormalities.

A decrease in the level of PAPP-A indicates the possible presence of a child with Down syndrome, Cornelia de Lange or Edwards. Elevated levels of hCG can speak not only about possible development Down syndrome. It increases with multiple pregnancy (the value increases several times according to the number of fetuses), an incorrectly set period and diabetes Mom. These values ​​may also be affected by the intake of certain medicines and weight of the pregnant woman.

The result of the ultrasound and the data from the analyzes of the first trimester should be interpreted and calculated by a geneticist or an obstetrician-gynecologist. There are special formulas and computer programs for this. Based on these data and individual characteristics pregnant patient (her ethnicity, age, obstetric history, the presence of genetic abnormalities in relatives), the doctor can put a woman at risk for Edwards or Down syndromes and neural tube defects.

In some cases, a geneticist may recommend that a woman undergo an additional chorionic villus biopsy. This examination gives an absolutely accurate answer to the question: does the child have chromosomal abnormalities, but it can lead to pregnancy complications, miscarriage or bleeding. The result of blood tests can be false positive when there is a threat of termination of pregnancy or dysfunction of the placenta. Therefore, screening can detect not only chromosomal abnormalities, but also other pathologies.

Diagnosis of trisomy in the second trimester of pregnancy

If a woman is scheduled for second trimester screening, this is not a cause for concern. These analyzes are recommended to everyone without exception. Prenatal screening for trisomy II trimester includes a triple biochemical examination (blood tests for hCG, AFP and free estriol), and from 20 to 24 weeks - an ultrasound study. Triple blood screening for hormones is most indicative from 16 to 18 weeks. The later it is carried out, the more difficult it is to interpret the results.

If the second screening showed elevated level alphafetoprotein, the child may have neural tube defects, Meckel syndrome, liver necrosis, or umbilical hernia. Decreased AFP levels indicate Edwards syndrome, Down syndrome, fetal death, or misdiagnosis. set time pregnancy.

Estriol is first produced by the placenta and then by the fetal liver. Therefore, if the pregnancy proceeds safely, its level is constantly increasing. A decrease in this substance in the blood of a pregnant woman may indicate the presence of chromosomal disorders, intrauterine infection, fetoplacental insufficiency and other pathologies. Too high a titer of this hormone is found in multiple pregnancies or large fetuses.

Based on the results of these examinations, if necessary, the doctor can refer the woman for analysis by invasive diagnostic methods (cordocentesis and amniocentesis). This analysis involves the invasion of the body of a pregnant woman in order to obtain samples for research, it can cause the development of some complications. The risk is approximately 2%.

Diagnosis of trisomy in the III trimester of pregnancy

At 32–34 weeks of gestation, a third ultrasound is performed, which can reveal malformations of the child with a late manifestation. In addition, the state of the placenta is carefully studied, the number of amniotic fluid and the position of the baby in the uterus. If necessary, conduct cardiotocography and Doppler study. These third trimester examinations allow you to monitor the condition of the fetus in late pregnancy.

With Doppler ultrasound, the degree of blood supply to the fetus is assessed using ultrasound: they check the speed of blood flow in the aorta and cerebral artery baby, as well as in the vessels of the umbilical cord and uterus. Based on the data of this analysis, a conclusion is made about whether there is enough oxygen and nutrients the child receives whether he is still comfortable in his mother's stomach. If the result shows insufficient blood supply, then the woman is prescribed drugs that improve blood flow and strengthen blood vessels. Sometimes they resort to emergency delivery.

During the ultrasound examination, the limbs of the fetus, the trunk, the head are measured for the second and third times, the fingers and toes are counted, the structures of the brain and internal organs are examined. This, with a high degree of probability, makes it possible to identify or exclude many pathologies.

The length of the nasal bone, the fronto-occipital and biparietal dimensions, the circumference of the abdomen and head, the length of the bones of the lower leg, shoulder, thigh and forearm, as well as the shape of some parts (nose, jaw, forehead) may be indicators of various anomalies.

What does newborn screening show?

There are a number of tests that are performed on newborns in without fail and at the request of the parents. Mandatory examinations reveal:

  • phenylketonuria;
  • galactosemia;
  • congenital hypothyroidism;
  • cystic fibrosis;
  • androgenital syndrome.

In order to exclude or identify these 5 severe hereditary diseases, on the 4th day of a child's life, the first screening is carried out - the so-called heel test. A few drops of blood are taken from his heel. The result of the examination is sent to the site where the baby will be observed in the future. If it is negative, then parents are not informed. And if one or more pathologies are confirmed, the doctor informs the parents or guardians of the baby about this and selects a specific treatment that will help avoid the child's disability in the future.

Additionally, it is possible to diagnose another 37 different metabolic disorders linked to heredity: the absence of certain enzymes or their insufficient activity. These include aminoacidopathy and aciduria.

Prenatal or prenatal screening of a pregnant woman, as well as newborn screening, can identify various pathologies and prevent the development of complications. In most cases, survey data provide negative results, which gives the parents of the child confidence that their baby is healthy and has no chromosomal abnormalities, some of which can be detected only after several years of the child's life, if such an examination is not carried out.

Prenatal screening is a set of special studies that are conducted for all expectant mothers to determine the risk of developing chromosomal abnormalities in the fetus. These studies are assigned to identify pregnant women who need a more detailed examination.

The presence of genetic abnormalities in the fetus is absolutely accurately shown only by methods of invasive diagnostics (that is, involving invasion of the uterine cavity in order to obtain biological material). However, their use is associated with a certain risk - the threat of abortion, the development of Rhesus conflict with negative Rh factor in a pregnant woman, infection of the fetus and some others. Therefore, these studies are prescribed only to expectant mothers who have a very high risk of fetal abnormalities. It is determined by screening tests. Screening tests are absolutely safe and therefore are carried out for all pregnant women without exception.

Currently, expectant mothers undergo a combined screening, which includes ultrasound and determination biochemical parameters blood - special hormones and proteins, the concentration of which changes significantly with genetic disorders fetus.

During pregnancy, it is desirable to undergo two biochemical screenings - in the first and second trimesters (double and triple tests, respectively).

Prenatal screening: double test

This study is carried out strictly in terms from the 11th to the 14th week of pregnancy. Using a double test in the first trimester, the risk of developing Down and Edwards syndromes and some other genetic abnormalities in the fetus is calculated.

In the first screening, two blood parameters are analyzed, which is why this study is also called a double test:

  • free b-subunit chorionic gonadotropin human (hCG);
  • PAPP-A is a plasma protein A associated with pregnancy. It is produced by the placenta, and its concentration gradually increases during the period of bearing the baby. Greatest growth this indicator is noted at the end of pregnancy. Low level PAPP-A may indicate fetal chromosomal abnormalities.

The risk of genetic abnormalities in the fetus is calculated using special computer programs. simple values the content of hCG and PAPP-A in the blood of a pregnant woman is not enough to decide whether the risk of chromosomal disorders in the fetus is increased or not. They must be converted into special values, the so-called MoM, showing how much this indicator deviates from the average value corresponding to a given gestational age. Thus, if the value of MoM y future mother close to one, which means that it coincides with the average value for all pregnant women for this period. Normally, MoM values ​​should be in the range from 0.5 to 2.

For accurate diagnosis, a blood test is always performed after a fetal ultrasound. This is necessary to clarify the gestational age, detect multiple pregnancies, detect visible disorders in the development of the fetus and placenta, etc. All these data are needed for the subsequent processing of the results of biochemical screening.

Deviations from the norm

In Down syndrome, free hCG rises to 2 MoM and above, and PAPP-A decreases to 0.48 MoM.

With Edwards syndrome (this is a disease characterized by multiple fetal defects in the presence of an additional 18th chromosome), both indicators are approximately at the level of 0.2 MoM.

With Patau syndrome (when an additional 13th chromosome appears in the fetus and multiple malformations also occur), both MoM indicators are at the level of 0.3–0.4 MoM.

On the analysis form, in addition to the MoM numbers, individual risks are also indicated separately for several diseases. For example, the result can be presented as follows: risk of Edwards syndrome: 1: 1600, risk of Down syndrome: 1: 1200. These figures show, for example, that the probability of having a child with Down syndrome is 1 in 1200 births, that is, out of 1200 of women with such blood test indicators, 1199 healthy children will be born and only one child will be sick.

Chromosomal abnormalities occur in approximately 0.6–1% of newborns. The most common are Down syndrome (frequency of occurrence 1 in 600–700 newborns), Edwards syndrome (frequency of occurrence 1: 6500), Patau syndrome (1: 7800), Shereshevsky-Turner syndrome (1: 3000 newborns).

Prenatal screening: triple test

Biochemical screening of the II trimester is carried out from 16 to 20 weeks of pregnancy (the optimal period is 16–18 weeks). It includes the determination of three indicators: total chorionic gonadotropin (hCG), the hormone estriol and alpha-fetoprotein protein (AFP) and is called triple test. Some commercial laboratories also test for the hormone inhibin A for greater accuracy.

A triple test allows 80% to detect malformations of the neural tube (that is, the spine, spinal cord and brain), as well as some genetic diseases (Down, Edwards, Klinefelter syndromes).

Alpha fetoprotein (AFP) is a protein produced during pregnancy. Its concentration increases gradually, as the duration of pregnancy increases, reaching a maximum at the 32–34th week, and then gradually decreases.

Deviations from the norm. elevated AFP level, more than 2 MoM, may be with multiple pregnancy, neural tube defects, umbilical hernia, developmental disorders of the esophagus and duodenum fetus. In Down syndrome and Edwards syndrome, the AFP level usually falls below 0.5 MoM.

Estriol free- the hormone of pregnancy, its concentration increases sharply during the period of gestation. Estriol is produced by the placenta and provides increased blood flow through the vessels of the uterus, active development ducts of the mammary glands and preparing them for breastfeeding. During the normal course of pregnancy, its level is actively growing. With a deterioration in the condition of the fetus, a sharp drop in this indicator can be observed. Normally, the concentration of estriol varies depending on the duration of pregnancy, gradually increasing from 0.45 to 40 nmol / l.

Deviations from the norm. A low level of estriol is observed in Down syndrome (less than 0.5 MoM), intrauterine infection, threatened miscarriage, impaired placental function, manifested in insufficient transport of oxygen and nutrients to the fetus with blood, when taking certain medications (for example, hormonal drugs and antibiotics).

An increase in the level of estriol by more than 2 MoM is observed with multiple pregnancies, impaired liver function in the expectant mother, and also with the bearing of a large fetus.

Inhibin A- This hormone is produced in the ovaries, placenta and fetal membranes.

Normally, the level of inhibin A also changes with increasing gestational age - from 150 pg / ml to early dates to 1246 pg / ml at 9–10 weeks, then the concentration of the hormone begins to decrease and at 18 weeks of pregnancy it ranges from 50 to 324 pg / ml.

Deviations from the norm. In Down syndrome, the level of inhibin is increased (more than 2 MoM). The concentration of inhibin A can also be influenced by external factors, for example, the level of inhibin in women who smoke is increased, and with high body weight it is reduced. When calculating the risk of developing fetal malformations, these factors must be taken into account.

It must be remembered that the concentration of b-hCG, PAPP-A and AFP in the blood can change not only with chromosomal abnormalities, but also with other complications of pregnancy: the threat of termination, intrauterine retention development, placental insufficiency, late toxicosis(gestosis). Also, the value of biochemical parameters is affected by the intake hormonal drugs and multiple pregnancy.

Prenatal screening: new in diagnostics

At the moment in prenatal diagnosis implemented the new kind research - non-invasive prenatal test. This analysis is based on the detection of fetal DNA in the blood of a pregnant woman, followed by the study and assessment of the likelihood of the presence of underlying genetic diseases. This method is very accurate (its accuracy is 99%) and absolutely safe for the expectant mother and fetus. However, these analyzes are not carried out in all laboratories and they are quite expensive.

If you are at risk...

Many expectant mothers, having received not very nice results biochemical screening, begin to worry strongly. But you shouldn't get upset. It must be understood that the probability of detecting a disease and the development of this disease is not the same thing. Revealing increased risk any deviation from normal flow pregnancy or normal development fetus is by no means a diagnosis. Pregnant women who are at risk are required to undergo special additional research to confirm or exclude the presence of pathology. Such expectant mothers are offered to pass invasive diagnostics. For example, amniocentesis is the collection of amniotic fluid with a special needle through the puncture of the anterior abdominal wall or through the cervical canal, cordocentesis - taking blood from the umbilical cord of the fetus and other studies.

Important addition

In the past few years, some commercial laboratories have also measured placental growth factor (PLGF) concentrations in their first trimester prenatal screening. This is a protein that is synthesized by the placenta and is involved in the formation of its vessels. This marker shows the likelihood of fetal growth retardation and the development of preeclampsia (a serious complication of the second half of pregnancy, which is manifested by an increase blood pressure, edema, the appearance of protein in the urine and requires emergency early delivery).

In a normal pregnancy, PLGF levels increase in the first and second trimesters and then decrease. In pregnancy complicated by preeclampsia, this indicator is reduced already in the first two trimesters. If an increased risk of this dangerous state and fetal growth retardation, special treatment is prescribed, early start which can significantly reduce the incidence of these diseases.

Mandatory or not?

More recently, all expectant mothers, without exception, had to undergo screening of the II trimester. But by order of the Ministry of Health of Russia No. 572n dated November 21, 2012, its mandatory women's consultations was cancelled. However, many commercial clinics continue to conduct this study.

Pregnancy does not always proceed against the background of complete well-being. To identify as early as possible possible pathologies and take appropriate measures, all pregnant women should not neglect registration and visits to doctors. One of the examinations provided for expectant mothers is screening. This is the name of a modern complex diagnostic method that gives the doctor information about the health of the child and the course of pregnancy. The first perinatal screening is carried out in the 1st trimester for a period of 10-14 weeks, the most optimum time the period from 11 to 12 weeks is considered. Screening includes ultrasound procedure and a blood test. The purpose of this method is to identify possible genetic abnormalities in the fetus.

Indications for perinatal screening in the first trimester

This examination is not included in the list of mandatory for all pregnant women and should be prescribed according to indications, and all other expectant mothers are limited only ultrasound diagnostics. But most often, doctors recommend that all women undergo it in order to exclude serious violations in the development of the fetus.

Indications for perinatal screening of the 1st trimester are the following factors:

  • in the anamnesis of women there were missed pregnancy, miscarriage, stillborn child;
  • one of the relatives of the spouses has genetic diseases;
  • in the first weeks of pregnancy, the woman was sick, took medication;
  • mother's age over 35;
  • one of the spouses in his life was exposed to radiation.
Ultrasound screening of the 1st trimester

The first step is to pass ultrasound diagnostics performed by a geneticist. The doctor will examine the following parameters:

  • embryo length (coccyx-parietal size);
  • the size of the collar zone, which is an important marker of pathologies at this time;
  • head and nasal bone size;
  • symmetry of the cerebral hemispheres;
  • bone length;
  • the size of the abdomen, heart;
  • matching location internal organs their places.

Having carefully studied all the data, the doctor may suspect the presence of a number of genetic diseases, for example, or Edwards, or their absence.

Perinatal biochemical screening of the 1st trimester

The second stage is the analysis of venous blood. Perinatal biochemical screening also called "double test". It includes the study of such placental proteins as PAPP-A and free b-hCG. Next, the data is processed in computer program according to the ultrasound results. Other data is also used for processing, for example, such as the woman's age, presence, diabetes, bad habits.

Deciphering perinatal screening of the 1st trimester

It is best to entrust the evaluation of the results of the diagnosis to the observing doctor, and not try to draw conclusions on your own. The results of perinatal screening of the 1st trimester after processing in a computer program are issued in the form of a special conclusion. It indicates the results of the study and calculated the risks of pathologies. The main indicator will be a special value, which is called MoM. It characterizes how the values ​​deviate from the norm. Experienced specialist, studying the form of the results of the study, will be able to see not only the risk of genetic abnormalities, but also the likelihood of other pathologies. For example, the values ​​of placental proteins may deviate from the norm of perinatal screening of the 1st trimester also with the threat of interruption, preeclampsia, fetal hypoxia and other obstetric pathologies.

If the examination showed high risk Down syndrome or another anomaly, then this cannot yet be considered an accurate diagnosis. The gynecologist will definitely issue a referral for a clarifying diagnosis.