Fitness and healthy lifestyle 

The blood flow in the venous duct is unidirectional. Venous duct. See the value of the Venous duct in other dictionaries

Fetal circulation is significantly different from that of an adult.

The fetus, it is in the womb, which means that it does not breathe with lungs - the ICC does not function in the fetus, only the BCC works.

The fetus has communications, they are also called fetal jesters, these include:

  1. foramen ovale (which throws blood from the RA into the LA)
  2. arterial (Batalov) duct (duct connecting the aorta and pulmonary trunk)
  3. venous duct (this duct connects the umbilical vein with the inferior vena cava)

After birth, these communications are closed over time, and if they are not closed, congenital malformations are formed.

Now we analyze in detail how the blood circulation occurs in a child.

The child and mother are separated from each other by the placenta, from which the umbilical cord goes to the baby, it includes the umbilical vein and umbilical artery.

Oxygen-enriched blood flows through the umbilical vein as part of the umbilical cord to the fetal liver, in the fetal liver, through the VENOUS DUCT, the umbilical vein is connected to the inferior vena cava. Remember that the inferior vena cava empties into the RA, in which there is an OVAL WINDOW, and blood through this window enters from the RA into the LA, here the blood mixes with a small amount of venous blood from the lungs. Further from the LA through the left interventricular septum into the left ventricle, and then enters the ascending aorta, then through the vessels to the upper body. Collecting in the SVC, the blood of the upper half of the body enters the RA, then to the pancreas, then to the pulmonary trunk. Recall that the ATRIAL DUCT connects the aorta and the pulmonary trunk, which means that the blood that entered the pulmonary table, for the most part, due to the high resistance in the vessels of the ICC, will not go to the lungs like in an adult, but through the arterial duct to the descending part of the aortic arch. Somewhere around 10% is thrown into the lungs.

The umbilical arteries carry blood from the tissues of the fetus to the placenta.

After the umbilical cord is tied, the ICC begins to function, as a result of the expansion of the lungs, which occurs with the first breath of the child.

Closing communications:

  • First, the venous duct closes by 4 weeks, and a round ligament of the liver forms in its place.
  • Then the ductus arteriosus closes, as a result of vasospasm due to hypoxia for 8 weeks.
  • The oval window is the last to close, during the first six months of life.

JNA)

see Ductus venosus.


1. Small medical encyclopedia. - M.: Medical Encyclopedia. 1991-96 2. First aid. - M.: Great Russian Encyclopedia. 1994 3. Encyclopedic dictionary of medical terms. - M.: Soviet Encyclopedia. - 1982-1984.

See what the "venous duct" is in other dictionaries:

    - (ductus venosus, PNA, JNA) see the list of anat. terms... Big Medical Dictionary

    venous duct- (ductus venosus) a vessel connecting the umbilical vein in the fetus with the inferior vena cava. It is located in the posterior part of the left longitudinal groove of the liver. After birth, the venous duct overgrows, turning into a venous ligament ...

    thoracic duct- (ductus thoracicus) the largest lymphatic vessel 30-40 cm long. It is formed in the upper abdominal cavity from the confluence of the right and left lumbar trunks. Along the length in the thoracic duct, the abdominal, thoracic and cervical parts are distinguished. AT… … Glossary of terms and concepts on human anatomy

    One of the two main lymphatic ducts. Lymph passes through it from both lower extremities, from the lower abdomen, the left half of the chest and head, and also from the left arm. The thoracic duct flows into the left venous angle. Source:… … medical terms

    THORACIC DUCT- (thoracic duct) one of the two main lymphatic ducts. Lymph passes through it from both lower extremities, from the lower abdomen, the left half of the chest and head, and also from the left arm. The thoracic duct flows into the left venous ... ... Explanatory Dictionary of Medicine

    BOTALLOV PROTOK- BOTAL DUCT, ductus arteriosus In talli (Leonardo Botallo, XVI century), is a vascular trunk that connects the aortic arch with the pulmonary artery (art. pulmonalis) in a uterine baby and is empty after birth. The development of B. p. stands at ... Big Medical Encyclopedia

    I The thoracic duct (ductus throracicus) is the main lymphatic collector that collects lymph from most of the human body and flows into the venous system. Passes G. p. only lymph flowing from the right half of the chest, head, neck and right upper ... ... Medical Encyclopedia

    Thoracic (lymphatic) duct (ductus thoracicus). Common iliac and lumbar lymph nodes- Front view. internal jugular vein (left); arch of the thoracic duct; the place where the thoracic duct enters the venous angle (the confluence of the internal jugular and subclavian veins; subclavian trunk (lymphatic), left; left brachiocephalic vein; ... ... Atlas of human anatomy

    right lymphatic duct- (ductus lymphaticus dexter) a short non-permanent vessel formed from the confluence of the right jugular, subclavian, bronchomediastinal trunks and opening into the right venous angle (the junction of the right internal jugular and subclavian veins) ... Glossary of terms and concepts on human anatomy

    - (ductus thoracicus, PNA, BNA, JNA) a lymphatic vessel through which the lymph flows into the venous channel from the legs, pelvis, walls and organs of the abdominal cavity, left arm, left half of the chest, head and neck; formed in the abdominal cavity by the fusion of the intestinal ... ... Big Medical Dictionary

    - (ductus lymphaticus dexter, PNA) a non-permanent lymphatic vessel formed by the fusion of the right jugular, subclavian, sometimes bronchomediastinal lymphatic trunks; flows into the right venous angle ... Big Medical Dictionary

Each pregnancy is not only the joy of waiting for the baby, but also the excitement about his development and health. Even the most carefree expectant mother once thinks about it. And for some women, this anxiety even drives them into a frenzy. A hundred years ago, a pregnant woman until the very birth did not suspect what her child would be like. But today, science allows you to “peep” in advance how the baby develops. For this, a woman is sent once a trimester for routine screening. Deciphering the results of screening of the 1st trimester is an exciting process, because it is now that most developmental pathologies are being detected. But don't worry ahead of time. The screening itself is absolutely safe, and its results are likely to please and reassure you.

1st trimester screening - what is it?

Prenatal screening is a set of measures and procedures carried out to assess the course of pregnancy and the condition of the fetus.

On the one hand, if, according to the results of the examination, everything is in order with the baby, the woman has no reason to worry. On the other hand, if pathologies are identified, she gets the right conscious choice determining her future life. Therefore, there is no reason to be afraid of screening. After all, if something is wrong with the fetus, it is advisable to find out about it as early as possible in order to decide on the advisability of maintaining the pregnancy. At the same time, a woman should know that no one can force her to terminate a pregnancy, just as no one has the right to forbid her to do so.

In the first trimester, screening consists of two parts - a biochemical analysis of maternal blood and an ultrasound examination of the fetus and uterus.

Ultrasound screening of the first trimester is a procedure that should precede the rest.

It is carried out to determine the following parameters:

  • fetometry (sizes of individual indicative anatomical structures) of the fetus;
  • condition of the uterus and its appendages;
  • the frequency of contractions of the heart muscle;
  • heart size, Bladder, stomach;
  • vascular condition.

The purpose of the examination is to determine the compliance of the parameters of the fetus with accepted standards. If a individual indicators differ from them, this is a reason to suspect a developmental pathology in a baby.

The second component of the first trimester screening is blood sampling from a vein future mother.

It is carried out in order to determine the level of two indicators:

  • the beta component of the hCG hormone;
  • PAPP - A or, as it is also called, protein A.

These values ​​should also be within strict limits, and their deviation from the norm usually indicates a violation in the development of the fetus or other adverse factors that threaten pregnancy.

These include pregnant women:

  • over the age of 35;
  • who are closely related to the father of the child;
  • undergoing any course of treatment;
  • having a history of pregnancy failures;
  • who gave birth to children with pathologies or who have such persons in their family.

But triggers some pathologies are still unknown. Therefore, anomalies can also occur in a fetus whose mother does not fall into any risk group.

Of course, no one can force a woman to be screened, but refusing screening is an irresponsible decision.

Timing of the first screening

As with the next two screenings, examinations at the beginning of pregnancy should be carried out in a strictly designated period. Blood sampling and ultrasound are most informative from the tenth week to the end of the thirteenth. If you undergo procedures in the 12th week, then all organs will be visualized.

At the beginning of pregnancy, changes in the body of the embryo occur very quickly, therefore every day carries new information. In this regard, it is better to complete the first screening in one day. It is permissible to visit the ultrasound room on the previous day so that in the morning next day donate blood to the laboratory.

What pathologies can be detected by first trimester screening?

Although the practice of referring every pregnant woman for screening has been around for many years, doctors rarely explain what it is for and how it “works”. Therefore, women usually go to the examination automatically, not understanding its importance. The main task of the first screening is to identify some of the most common pathologies in the fetus, if present.

Signs of Down syndrome on ultrasound

Down syndrome is a chromosomal pathology that is found in every 700th fetus. Thanks to screenings, the number of babies born with this disease last years decreased by almost half.



The disease is directly dependent on the age of the mother, therefore, all women who have reached the age of 35 automatically fall into the risk group. Pathology develops at the time of fertilization and, according to geneticists, does not depend on the lifestyle and habits of the pregnant woman. Down syndrome occurs when extra chromosome and is called trisomy 21. As a result of such a chromosomal disorder, the child develops severe heart defects, digestive organs and other systems. Children with this pathology are mentally retarded and have a characteristic appearance.

At the first screening, several facts can tell about a chromosomal disorder.

  1. Expanded collar space. For more later dates the child develops lymphatic system and this parameter ceases to be informative.
  2. Not rendered nasal bone. This is true for 60-70% of children with Down syndrome. At the same time, 2% healthy babies the nasal bone is also not visible at the indicated dates.
  3. Smoothed facial features.
  4. The blood flow is different from normal in 8 cases out of 10. But for 5% of children without any pathologies, this is the norm.
  5. An enlarged bladder can also indicate trisomy.
  6. Reduced, relative to the norm, the maxillary bone.
  7. One, instead of two, umbilical artery. Such an anomaly is characteristic of many chromosomal pathologies.
  8. Tachycardia also indicates various malformations, including Down's syndrome.

Children with this disease may well live to give birth and then exist for quite a long time. But this does not alleviate their fate as severely disabled people who constantly need help and control.

Patau Syndrome

Another one chromosomal abnormality, which develops in one in 10 thousand babies. The disease is caused by an extra 13th chromosome. Genetic failure can occur at any time of gestation and affect both the entire body and only individual bodies. Sometimes the pathology is mild.

On ultrasound, the doctor may suspect Patau syndrome for the following signs:

  • tachycardia;
  • asymmetric development of the cerebral hemispheres or its underdevelopment;
  • slow formation of the skeleton and, as a result, discrepancy between the lengths of the bones to accepted standards;
  • hernia caused by late formation of the abdominal muscles.

Children born with the described syndrome rarely live longer than a few months and almost never longer than a year. Most clear signs pathologies will be distinguishable closer to the second screening.

Edwards syndrome

This is a chromosomal failure caused by the presence of a third in the 18th chromosome set. Pathology is also congenital and today there is no reliable data on what provokes it and how to prevent it. The cause of the extra chromosome is an abnormal gamete.


In a sick fetus, ultrasound fixes:

  • high heart rate;
  • the absence of the nasal bone at this time;
  • one umbilical artery instead of two;
  • umbilical hernia.

Children with Edwards syndrome are born small, although the gestation period is normal. Babies have many malformations (heart, gastrointestinal tract, lungs), which rarely allow them to live up to a year.

Smith-Opitz syndrome

This pathology is characterized by a metabolic disorder and is caused by a mutation of a certain gene. Children born with this problem may have facial anomalies, lag in mental development, six-fingered. On the first ultrasound, the pathology has almost no characteristic signs, except for an increase in the collar space. At a later date, oligohydramnios and specific skeletal deformities may be observed. The disease is diagnosed mainly by amnio- or cordocentesis.

A gene mutation can manifest itself weakly, then it is classified as the first type and the baby has every chance of living, but lagging behind mentally and physically from peers. With the syndrome of the second type, newborns most often die.

de Lange syndrome

Another genetic failure, the causes and triggering mechanism of which have not yet been sufficiently studied. It is manifested by multiple pathologies of the skeletal structure, facial anomalies and impaired functioning of internal organs. characteristic feature- thin upper lip, thin, fused eyebrows and thick, long eyelashes. It is rare, only in one case out of 30 thousand.



It is almost impossible to diagnose pathology in the embryonic period. Its presence may be indicated by the absence of protein-A in the mother's blood. But it is unacceptable to make a diagnosis based only on this sign, since in 5% of cases a false positive result is also found. Closer to the second screening, the fetus may experience a discrepancy in the size of the bones to the norms.

As you can see, on specified period according to ultrasound, it is only possible to reliably diagnose the presence of a pathology, but it is difficult to accurately name its type. More reliable results can be obtained by analysis of the chorionic villi or a second screening.

What do they find out at the first screening?

The data obtained in the laboratory are still intended for a doctor, and not for the inquisitive mind of a worried expectant mother. Remember that no one is specifically interested in intimidating you or hiding the real state of things. Therefore, rely on the experience of the doctor conducting the pregnancy, and give him the privilege of reading the screening protocol.



HCG norm

This hormone is called the main one during pregnancy. It grows from conception and reaches maximum concentration by 11-12 weeks. Then it falls a little and remains at the level until childbirth.

If hCG is elevated, this may indicate:

  • maternal diabetes;
  • multiple pregnancy;
  • Down syndrome in the fetus;
  • toxicosis.

Reduced hCG is detected when:

  • the threat of miscarriage;
  • tubal pregnancy;
  • Edwards syndrome.

In different laboratories, the parameters may differ, so you should not focus on quantitative indicator, but on the MoM coefficient, which we will discuss below.

Norma RAPP-A

This is the name of the protein that the placenta produces. Its concentration is constantly growing. If this figure is higher than normal with other normal data, then there is no reason to worry. You should be concerned if the protein concentration is low.

This may be a sign:

Heart rate (HR)

The fetal heart beats faster than that of an adult, but tachycardia may be one of the signs of developmental pathology. If the fetal heartbeat is not audible on ultrasound, then this definitely indicates a missed pregnancy.

Collar zone thickness (TVZ)

This is the most indicative parameter for the indicated period, the deviation of which from the norm almost always indicates pathologies. It is also called the thickness of the collar space. This is the distance from the skin to the soft tissues covering the neck of the embryo. Normally, this indicator, depending on the gestational age, is 0.7-2.7 mm. It is measured during the period when the length of the fetus from the head to the coccyx is in the range from 45 to 85 mm. At a later date, TVZ (TVP) becomes uninformative.

Coccyx-parietal size of the fetus (KTR)

This parameter is relevant for the 10-12th week. It is measured from the crown to the tailbone and allows you to set the gestational age as accurately as possible. Already from the end of the 12th week, the baby begins to raise his head and other parameters become indicative.

Nose bone length

The nose is a quadrangular bone, the shortening of which clearly indicates pathological processes in the development of the fetus. It happens that this bone is completely absent, which signals the most complex anomalies that are quite rare. Underdevelopment of the nasal bone (hypoplasia) may result from the described syndromes and other disorders.

Fetal head size (BDP)

On the early dates baby's head is most his body, and his brain is developing rapidly. Because the size of the head - the most important indicator characterizing the state of the fetus. Of particular importance is biparietal size measured from temple to temple. If this parameter is above the norm, then the rest of the indicators are evaluated first. It happens that the fetus is just large and then all fetometry data exceed the norm. But big values BPD may also indicate cerebral hernia, tumors, or hydrocephalus.

All norms of the described data for weeks are shown in the table below.

Table 1. 1st trimester screening, norms

Please note that the deviation of some parameters by just a millimeter already speaks of pathologies, but no one excludes the banal inaccuracy of measurements. Therefore, responsibly approach the choice of the place where you will undergo the examination.

MoM coefficient

If everything is clear with the units of measurement of fetal parameters, then the results of blood biochemistry require a separate explanation. Each laboratory has its own software and therefore results may vary. To unify the data obtained, it is customary to reduce them to a special coefficient called MoM. Indicators from 0.5 MoM to 2.5 do not cause concern. But the closer they are to one, the better. In the study protocol, the laboratory will most likely indicate the amount of hormones and then the MoM coefficient.

Getting ready for research

Due to the fact that the fetus is still very small, you will have to prepare a little for the first ultrasound. The examination can be carried out with a vaginal probe or along the anterior abdominal wall. Everything will depend on the position of the embryo.

  1. In the first case, no preparation is required. The doctor will introduce special device, protected by a condom, into the vagina and perform gentle manipulations. The procedure does not cause any discomfort, but, within two days after it, slight bleeding may be observed.
  2. Conducting ultrasound through abdominal wall absolutely safe and painless. But in order for the doctor to be able to examine the embryo, you must first fill the bladder. To do this, drink at least half a liter of liquid an hour and a half before the procedure. it required condition, without which the doctor simply will not see anything.


The light pressure of the sensor on the filled bladder is not very pleasant, but any woman can cope with these sensations. Near each ultrasound room there is a toilet where you can finally relax when the procedure is completed.

Before an ultrasound, it is also undesirable to drink carbonated drinks and eat food that provokes flatulence.

Biochemical screening of the 1st trimester in without fail is carried out on an empty stomach.

  1. A day before blood sampling, refrain from eating any food that can cause allergies. Even if you have never had atypical reactions to food.
  2. Be sure to exclude nicotine and alcohol, and for the entire period of pregnancy, and not just before the tests.
  3. Do not consume oily and fried food. It is better to exclude smoked products and products with a long shelf life.
  4. If you take any medications on an ongoing basis, be sure to indicate this on the questionnaire. If you are undergoing any treatment, postpone the screening until it is completed if possible.

The expectant mother receives the results of the ultrasound immediately, but the response of the laboratory for biochemical analysis has to wait a week and a half.

Deciphering the results

Having received the ultrasound and biochemistry data, the woman goes to her gynecologist, who analyzes the information received. If the results are satisfactory and the woman is not at risk, additional tests not required. There is no point in further examinations in the case of a frozen or regressing pregnancy. When the screening data is unsatisfactory, a woman is recommended to consult a geneticist.

Deciphering research data on your own is risky. But if you are itching to understand the numbers that are on hand, note that the laboratory usually gives results in the form of a fraction. The closer its value is to 1, the more serious the situation. That is, an indicator of 1:10 is much worse than 1:100, and 1:100 is worse than 1:300. This ratio shows how much healthy children in your conditions it is necessary for one with the specified pathology. For example, if you find the entry "trisomy 21 - 1:1500" in the lab's response, this means that the risk of having a baby with Down's disease is 1 in 1500. This is a very small probability and you can relax. The boundary ratio is considered to be 1:380.

Remember that even a high risk is not yet a reason for panic, and even more so for an urgent termination of pregnancy. You still have invasive diagnostic methods.

And only they can give a clear answer whether your baby has a pathology, and not in theory in a group of people with similar parameters.

Safety for mother and fetus

By itself, prenatal screening of the 1st trimester does not pose any danger to either the mother or the fetus. Ultrasound does not affect the fetus, although it is not known for certain whether the examination causes discomfort to the baby. Some experts are of the opinion that the child hears during the procedure loud noise, which may be unpleasant to him, but definitely not dangerous.



Blood for biochemistry is taken from a future mother from a vein, which is also completely harmless, although not very pleasant. Some women are very afraid of this procedure and even lose consciousness in the process. If you are in this category, tell the nurse to have ammonia ready.

If the results obtained are satisfactory, then this is usually stopped until the next screening. When the data raises concerns, you will need to resort to additional methods diagnostics. At the beginning of pregnancy, this is a chorionic villus biopsy or amniocentesis. The first method allows you to determine with 100% accuracy whether there are congenital pathologies in the fetus, but too often it leads to a miscarriage. Amniocentesis is less dangerous, but even this procedure results in a spontaneous abortion in one in 200 cases.

What to do with adverse results?

Absolutely unequivocally, the doctor should interpret the results of screening. Not having sufficient knowledge, the expectant mother will only bring fear upon herself, not understanding the numbers received. For example, boundary data for Down's disease with a very highly likely will be in a 40-year-old woman who became pregnant through IVF. This does not mean at all that something is wrong with her pregnancy specifically. The risks of pathology in the group of women of this age are simply high.

Therefore, having received results that inspire concern, discuss with your doctor. And maybe not just one. If finances allow, take the tests in another laboratory. Often, doctors recommend not to panic ahead of time and wait for the results of the second screening, which can be done starting from the 15th week.

On which ultrasound can a doctor determine the sex of a child?

Ultrasound is not only a diagnostic method, but also an opportunity to know in advance the gender of your baby. Theoretically, this becomes possible already from the 12th week, when the labia in girls and the penis in boys are visualized. A more realistic period when gender can already be determined unmistakably is fifteen weeks. The only problem is that the fetus unfolds right place to the sensor. Alas, this does not happen at the request of the mother and does not depend on the manipulations of the doctor. Sometimes, despite all the tricks, the baby does not reveal his main secret right up to the birth.

Screening is not a cause for concern, but simply a diagnostic tool. Today, thanks to the Internet, expectant mothers have access to all the knowledge of the world. Unfortunately, the information available is often misleading and scary. But now, when you are already responsible for two lives, the main thing is not to worry. Therefore, do not expect unpleasant surprises from pregnancy and follow the doctor's instructions.

Related videos

In the second trimester, if necessary, a second screening during pregnancy is prescribed, which should confirm or refute the data obtained during the first comprehensive examination. Changes in the results are carefully studied, compared with standard indicators, and appropriate conclusions are drawn.

On their basis, parents receive information about the prenatal state of the child. If it is positive, it remains only to wait for his safe birth. If negative, it is necessary to take appropriate measures - treatment or artificially induced premature birth. In any case, the second screening is a responsible procedure for which you need to be mentally and physically prepared.

Goals

Those who have already passed the first comprehensive examination well know and understand why they do a second screening during pregnancy. The goals of this procedure are:

  • identify those defects that could not be determined after the first screening;
  • confirm or refute the diagnoses previously made in the first trimester;
  • establish the level of risk of pathologies;
  • to detect physiological deviations in the formation of the child's body systems.
  • high hCG;
  • low EZ and AFP.
  • all blood counts are low.

Neural tube defect:

  • normal hcg.
  • high E3 and AFP.

Not always a bad second screening guarantees 100% staging accurate diagnosis. There were cases when quite healthy children were born after it. Even medicine fails. But you should not count on the fact that this is exactly your case. In this matter, it is better to focus on the opinion and recommendations of the gynecologist observing the pregnancy. It is he, as a professional, who can take into account the possibility of a false result, which is determined by many different factors.

False results

Although rare, this happens: second trimester screening gives false results. This is possible if the course of pregnancy is characterized by the following features:

  • multiple pregnancy;
  • incorrectly set deadline;
  • excess weight overestimates the indicators, insufficient - underestimates them;

Before the second screening, the gynecologist must identify these factors with the help of a questionnaire and a preliminary examination and take them into account when deriving the results. It will depend on this further actions to maintain or terminate a pregnancy.

Further actions


Since the second screening during pregnancy is carried out already in its middle, abortion in case of detection of severe genetic abnormalities is impossible. What actions can the doctor advise in this case?

  1. Consultation with a gynecologist about the data obtained if the risk of developing abnormalities is 1:250 or 1:360.
  2. Carrying out invasive diagnostic methods at the risk of pathologies 1:100.
  3. When confirming the diagnosis, which is not amenable to therapeutic adjustment, it is recommended that the fetus be removed.
  4. If the pathology is reversible, treatment is prescribed.

The second screening quite often ends in induced labor, and married couple must be mentally prepared for this. Since a lot depends on these procedures, young parents need to know as much information about them as possible, which will help to understand incomprehensible issues and dispel doubts.

And other features

Before the second screening procedures, a couple always has a lot of questions about how to properly prepare for them and how exactly they go. The doctor does not always have time to conduct detailed educational work on this matter, so you often have to look for answers yourself. A special block will help to facilitate this task.

When is the second screening done?

From the 16th to the 20th week.

Do I need to donate blood at the second screening?

If the ultrasound showed deviations, then it is necessary. If there are no suspicions of genetic disorders, the doctor may not prescribe a blood biochemistry test.

What is included in the second screening during pregnancy?

ultrasound and biochemical analysis blood taken from a vein.

What is revealed at the second screening?

Genetic disorders in the development of the fetus and placenta.

Is it necessary to do a second screening?

At the first bad screening - definitely.

How should hCG change at the second screening?

Compared to the results of the first screening, its indicators are temporarily reduced.

Can I eat before the second screening?

You can not eat 4 hours before the second screening, as this may distort the results of the studies.

In some cases, doubts about whether the fetus has developmental abnormalities can only be dispelled or confirmed by a second screening. If the results of the first showed too high a risk of gene mutations, but the pregnancy was not interrupted, a comprehensive study must be completed. This allows not only to soberly assess the situation, but also to make an informed decision about whether to give birth to a sick baby or not. The question is difficult, but it is impossible not to pay attention to it: not only the life of the child, but also the fate of the parents themselves depends on it.

This type of examination is prescribed for women who are diagnosed with 11-13 weeks of pregnancy. First stage the first screening during pregnancy - ultrasound. After that, the pregnant woman is sent for a biochemical blood test.

Such events make it possible to identify genetic defects, pathologies in the structure of the embryo and respond to them in a timely manner.

How to prepare for the first screening?

The procedure under consideration includes two types of examination, each of which needs a certain preparation.

ultrasound

Can be done in two ways:

  1. External (abdominal). It is given with a full bladder, therefore, 30-60 minutes before the start of the procedure, the pregnant woman must drink at least half a liter of purified water without gas, or not urinate 3-4 hours before the start of the ultrasound.
  2. Vaginal. This type examination does not require special preparation. Some clinics require patients to come to the appointment with their own diaper, sterile gloves and a condom for the ultrasound transducer. All this can be purchased at almost any pharmacy.

(double test)

It provides for the following preparatory measures, ignoring which can significantly affect the test results:

  • 2-3 days before the analysis, a pregnant woman should refrain from fatty, salty foods (meat, seafood), citrus fruits and chocolate. The same goes for multivitamins.
  • Blood must be donated on an empty stomach. The last meal should be at least 4 hours before the test.
  • Doctors also advise to exclude sexual intercourse a couple of days before the screening.

How does the first screening in pregnant women go and what does it show?

The indicated type of examination should be started with. After all, it is ultrasound diagnostics that makes it possible to determine the exact gestational age - and this very important for the second stage of screening: the double test. After all, the indicators of the blood norm, for example, for 11 and 13 weeks will be different.

In addition, if an ultrasound scan detects the fetal fading or the presence of serious anomalies in it, there will be no need for a biochemical blood test.

Thus, at the time of passing the second stage of the first screening, the pregnant woman should have the conclusion of an ultrasound doctor in her hands.

Ultrasound procedure

The type of examination under consideration favors the identification of such physical defects of the fetus:

  • developmental delay.
  • The presence of serious pathologies.

Also thanks to ultrasound the gestational age is determined, the number of fetuses in the uterus, the approximate date of birth is set.


In the first third of pregnancy, the following indicators are checked on an ultrasound machine:

  1. The distance from the coccyx to the parietal part of the head. This parameter is also called the coccygeal-parietal size (KTR). At the 11th week of pregnancy, the CTE varies within 42-50 mm, at the 12th week - 51-59 mm, at the 13th - 62-73 mm.
  2. The size of the nasal bone. At the 11th week, it is not visualized. At 12-13 weeks, its parameters are more than 3 mm.
  3. The distance between the tubercles of the parietal region, or biparietal size (BDP). Fine this indicator should be 17 mm at week 11; 20 mm at 12 weeks; 26 mm at the 13th week of pregnancy.
  4. Embryo head circumference.
  5. The distance from the forehead to the back of the head.
  6. The structure of the brain, symmetry and size of its hemispheres, the quality of the closed skull.
  7. Heart rate (HR). By means of this parameter, cardiac arrhythmia can be detected. When measuring the heart rate, the sonographer must be very careful: due to the short duration of pregnancy, it is possible to confuse the pulsation of the patient's vessels with the heartbeat of the embryo. Normally, the indicator in question varies between: 153-177 at the 11th week of pregnancy; 150-174 - at the 12th week; 147-171 - on the 13th.
  8. Parameters of the heart and its arteries.
  9. The structure of the femur, shoulder, tibia.
  10. Distance between inner and outer surface skin neck, or the thickness of the collar space (TVP). Normally, this indicator will be: at the 11th week of pregnancy 1.6-2.4 mm; at the 12th week - 1.6-2.5 mm; at the 13th week - 1.7-2.7 mm.
  11. The structure of the chorion (placenta), its location. Upon detection of exfoliation of the chorion, its volumes are established and whether there is a tendency to progress. Such a phenomenon may lead to bloody issues and complaints of a pregnant woman about pain.
  12. Shape and size of the yolk sac, the quality of supply of the umbilical cord with vessels. Yolk sac normally, by the 12th week of pregnancy, it decreases in size, and at the time of the procedure, it should be a scanty (4-6 mm) cystic neoplasm of a rounded shape.
  13. The structure of the uterus, its appendages. Special attention give to the ovaries: in the later stages of pregnancy, it is problematic to examine them.

At the time of the first screening ultrasound the fetus must be positioned correctly so that the specialist can carry out a qualitative inspection and make the necessary measurements.

If the child is not positioned correctly, the patient is asked to roll over from her back to her side, cough, or squat.

Double test (norms and interpretation)

For this type of examination, blood is used from a vein, which is taken on an empty stomach.


Biochemical screening is needed to determine the following parameters:

1.Protein Pregnancy (PAAP) -A )

This protein is produced by the placenta and increases with the course of pregnancy.

Normally, the indicators of this protein will be as follows:

  • 11-12 weeks: 0.77-4.76 honey / ml.
  • 12-13 weeks: 1.04-6.01 mU / ml.
  • 13-14 weeks: 1.48-8.54 mU / ml.

A reduced amount of PAAP-A may be due to the following deviations:

  1. There is a threat of miscarriage.
  2. The developing embryo has Down syndrome, Edwards syndrome, or another genetic disease.

An increase in the level of PAAP-P in the blood of a future mother often does not have an important diagnostic value.

2. Amounts of human chorionic gonadotropin (hCG)

This hormone is produced in the first weeks of pregnancy, reaching a maximum level at the 12th week of pregnancy, after which the amount of the hormone in question decreases.

By studying the indicators of the amount of hCG in the blood of a pregnant woman, it is possible to determine the presence / absence of chromosomal abnormalities.

In the conclusion sheet, this parameter is written in the column “free β-hCG”.

In the first trimester of pregnancy, the norm of this hormone is as follows:

  • 11th week: 17.3-130.2 ng / ml.
  • 12th week: 13.3-128.4 ng / ml.
  • 13th week: 14.3-114.7 ng / ml.

Inflated figures hCG levels may indicate several things:

  • At developing fetus Down syndrome.
  • The mother-to-be has diabetes.
  • The pregnant woman suffers from severe toxicosis.

A decrease in the level of the hormone in question may occur against the background of the following factors:

  • There is a risk of miscarriage.
  • Pregnancy formed outside the uterine cavity
  • Failure of the placenta to perform its basic functions.
  • The fetus has Edwards syndrome.

What pathologies can be detected on the screening of the first trimester?

In the first three months of pregnancy, through examinations, it is possible to identify or suspect the presence of the following ailments:

  • Errors in the structure of the neural tube (meningocele).
  • Down Syndrome. The prevalence of this disease: 1:700. Timely detection of this pathology made it possible to reduce the birth rate of sick babies (1 per 1100 cases).
  • Umbilical hernia (omphalocele). An ultrasound study shows that internal organs are located in the hernial sac, and not in the abdominal cavity.
  • Edwards syndrome (1:7000). It is characterized by a reduced heart rate, omphalocele, insufficient amount of blood vessels on the umbilical cord, the absence (inability to visualize) the nasal bone. Pregnant women over 35 years of age are at risk.
  • triploidy. With this pathology, instead of 46, there are 69 chromosomes in a fertilized egg. Such a phenomenon may occur due to an incorrect structure of the egg, or when two spermatozoa penetrate one egg. Often, with such anomalies, women do not bear a fetus, or give birth to dead children. In those rare cases when it was possible to give birth to a live baby, the period of his life is limited to a few days / weeks.
  • Patau disease (1:10000). Ultrasound ascertains retardation in the structure of the brain, tubular bones, increased heart rate, omphalocele. Often, babies that are born with a similar diagnosis live a maximum of a couple of months.
  • Smith-Lemli-Opitz syndrome (1:30000). It is the result of genetic disorders, due to which the qualitative assimilation of cholesterol is impossible. The pathology under consideration is capable of provoking many malformations in development, the most serious of which are errors in the functioning of the brain and internal organs.

To confirm some of the above pathologies, it is required additional diagnostic measures , and in most cases they are invasive.


What can affect the results, and can the doctor make a mistake at the first screening?

Screening for the first trimester of pregnancy has certain disadvantages.

On the other hand, the survey still needs to be carried out: timely detection This or that pathology will make it possible to terminate the pregnancy (if the fetus is severely abnormal), or take measures to maintain the pregnancy (if there is a threat).

In any case, it will be useful for any expectant mother to know that false positive screening results can occur in the following situations:

  1. ECO. At artificial insemination the parameters of the occipital part of the embryo will be 10-15% higher than normal. Double test will show increased amount hcg, and low level(up to 20%) RAAP-A.
  2. Weight of the expectant mother: severe thinness is a consequence of a decrease in the amount of hormones, and with obesity, the opposite phenomenon is observed.
  3. Diabetes, other diseases work-related thyroid system. With such ailments, it is problematic to calculate the risks of diseases in the fetus. Often, doctors cancel screening for this reason.
  4. Multiple pregnancy. Due to the inability to date to accurately determine hormonal background a pregnant woman with more than 1 child, her screening is limited to ultrasound and does not include biochemical analysis.

Most expectant mothers feel in one way or another fears about the baby in the womb. As a rule, they do not have soil under them. But in some cases, these fears are so strong that it is better for the expectant mother to undergo a first trimester screening and continue to wait for the baby calmly. Sometimes this study is recommended by doctors to allow the pregnant woman to decide whether to prolong the pregnancy or the risks are too high.

All pregnant women can undergo screening in the first trimester with the consent of both future parents of the baby. In cases where these are the doctor's recommendations, and the risk of having a sick baby is increased, this examination should be done without fail.

Among the reasons that should encourage a pregnant woman to undergo the first screening during pregnancy will be:

  • Close family relationship of the pregnant woman with the father of the baby;
  • The presence of close relatives of both parents with congenital pathologies;
  • The presence of a pregnant baby with congenital pathologies;
  • Age of the future mother (over 35 years old).

Among the reasons for screening in the first trimester will also be those related to the woman's previous pregnancies:

  • Presence of fetal fading;
  • stillbirth;
  • Having 2 or more miscarriages;

Risk factors will also include those cases that are associated with:

  • With the use of drugs prohibited during pregnancy (even when it was vital);
  • With the mother, during pregnancy, viral or bacterial diseases.

The referral for the first screening will be written by the gynecologist who observes the pregnant woman. But the place of examination must be chosen by the pregnant woman herself.

It should be noted here that this survey is carried out in 2 stages. The first is an ultrasound, and the second is biochemical research blood, where to determine the amount of hCG and PAPP-A hormones. It would be better if a woman passes both examinations on the same day, and for this it is good to choose perinatal center where both are made.

How is the research done?

An ultrasound should be done first, and then blood sampling from a vein for hCG and PAPP-A.

Ultrasound screening of the 1st trimester is carried out in two ways:

  • transvaginally
  • Abdominally

The doctor will choose only one of the ways. In a transvaginal exam, a very thin probe is inserted into the vagina. To do this, the woman lies on the couch without clothes below the waist, bends her knees and slightly spreads. A transducer placed in a condom is inserted into the vagina. None discomfort is not observed. But sometimes on the second day there may be slight spotting.

In abdominal screening, the examination is done through the abdomen and requires a full bladder. And you should be prepared for this. In this case, the sensor is located on the skin of the abdomen. Here you just need to lie down on the couch and free your stomach from clothes. During the second screening (in the second trimester), abdominal filling of the bladder is not required.

The results of the ultrasound will be handed out and they need to undergo biochemical screening.

Biochemical screening, what is it?

The second screening is blood sampling from a vein. During its conduct, in addition to the results of ultrasound, the pregnant woman will be asked a number of questions that are essential for screening.

Then 10 ml of blood will be taken from a vein. The results of this examination are usually ready no earlier than in a few weeks (hCG and PAPP-A). Then they will issue a conclusion.

Dates

First trimester screening is very time-limited. The accuracy of the result will depend on the correctness of their determination. Therefore, it is important to conduct an examination no earlier than the 1st day of the 11th week and no later than the 6th day of the 13th week of pregnancy. If necessary this survey the calculation of the term is made taking into account the anamnesis, as well as last menstrual period. Usually, when referring to a screening by a gynecologist, pregnancy calculations are performed again and the day of the examination is determined.

Training

Such a complex and responsible procedure requires some preparation. In order to prepare well for screening, a number of features of the procedure should be taken into account. Since two examinations are performed at once: an ultrasound examination and blood sampling from a vein, they differ somewhat in preparation. The general will be the preparation on the day before the examination (it is also possible two or three days before). This screening preparation is needed

for more accurate results of a biochemical blood test (hCG and PAPP-A). Here is the diet to follow:

  • Exclude allergenic products from the diet;
  • Do not eat fatty and fried foods;
  • Do not eat seafood and smoked meats;
  • Don't eat chocolate.

Non-compliance with the diet will lead to an increased risk of not. Directly on the day of the procedure, you should fast 4 hours before donating blood for a biochemical analysis, if the ultrasound is performed abdominally, 30 minutes - 1 hour you should start drinking water without gas or you can, if possible, not urinate 2-3 hours before the examination . When examining transvaginally, no preparations are needed. As noted earlier, you first need to undergo (usually before 11 o'clock in the afternoon) an ultrasound examination, and then donate blood.

Deciphering the results

Deciphering the results usually takes long time(up to 2-3 weeks). It is carried out with the help special program prisca. The decoding includes not only ultrasound and biochemical screening, but also monitoring the condition of the pregnant woman, as well as family history. One of the points will be the question: is it necessary to undergo a re-examination at a later date?

More screening results will give an answer to a large number of questions. Among which will be:

  • How high is the risk congenital pathologies in the fetus?
  • Which of the possible genetic diseases are possible and what is their probability?
  • Should pregnancy be prolonged?

At ultrasound examination define five main criteria, they can say a lot about possible pathologies and the likelihood of their occurrence.

So, the first screening will show the parameters of the coccyx-parietal size (KTR) of the fetus, which are an indicator general development fetus and are characterized for each week very individually.

For possible development some chromosomal diseases it is important to study the thickness of the collar zone (TVZ) in case of deviation from the norm, there is a suspicion of Down syndrome and some other complex chromosomal pathologies.

In this regard, the nasal bone is also very important. Which, in a fetus with this disease (60–70%), is formed much later or is absent. It is not determined by ultrasound in about 2% of healthy children. Much later, it is also determined in pathologies such as Pattau's syndrome. The norm, when it is visible already at 11 weeks.

One of important conditions the absence of pathologies will be the frequency heart rate. Its violation may indicate several pathologies: Down syndrome, Edwards syndrome, Pattau syndrome.

During this period, the presence of an umbilical hernia (omphalocele) is already determined, when the internal organs of the peritoneum are in a thin bag of skin outside the abdominal cavity.

And also look for the presence of a reverse venous blood flow, which indicates trisomy (the presence of a trio of chromosomes instead of two, which usually indicates the occurrence of severe genetic diseases).

And the presence of one umbilical artery instead of two, which is often a sign of Edwards Syndrome or indicates an omphalocele.

The table below shows the data that represent the norm for the fetus at this stage of development. Comparing with them the data of ultrasound screening of the first trimester of a pregnant woman, one can judge the development of the fetus.

Indicators of screening studies in the first trimester of pregnancy (normal)

What hormone norms are determined by the first screening

When conducting biochemical screening (blood test), the level of two types of hCG and PAPP-A hormones is determined:
HCG (chorionic gonadotropin) is a hormone that is called the hormone of pregnancy, its amount in the body of a woman increases when pregnancy occurs (a pregnancy test is based on this factor). It is bad if its level is increased or decreased. At increased rates increased risk of developing Down syndrome reduced rates risk of Edwards syndrome or placental pathology. The table below shows the normal values.

The second hormone that is being studied is called PAPP-A (plasma protein-A). This is the protein that the placenta produces, and, therefore, with an increase in the duration of pregnancy, its concentration in the blood increases. By the amount of PAPP-A produced, it is possible to judge some chromosomal pathologies of the fetus. Among them will be:

  • Edwards syndrome;
  • Down syndrome;
  • Cornelli de Lange syndrome
  • Rubinstein-Taybi Syndrome
  • Mental underdevelopment with hypertrichosis.

The fact is that at these times the screening ultrasound examination is not always accurate enough, so the results of biochemical screening are very important. If the result is increased or decreased in comparison with the norm, then this is already an alarming bell.

The table below shows the results of screening, in which the norm for this hormone is observed.

MoM coefficient

When handing over the results, there will be such an indicator as the MOM coefficient.

The fact is that there is a norm for a given area and the age of a pregnant woman, which, using a special prisca program, is converted into a median. The ratio of the indicators of a pregnant woman to this norm will be an indicator of MoM. Normally, when the indicator ranges from 0.5 to 2.5, and ideally when it is close to 1. The entry in the result form should look something like this “hCG 1.2 MoM” or “PAPP-A 2.0 MoM”, if this indicator is increased - it is always bad.

Research Risks

In addition to the MoM indicators in the results form, there will also be a risk assessment: which can be “High” or “Low”, normally when it is “Low”. Usually this is a number with a fraction, for example, 1:370 than more fraction, all the better. It is desirable that the figure be greater than 380. This means that at the birth of 380 babies, one child may have Down's disease. Here, the higher the number (more than 380) the better. Such risks are defined as "Low".

Important. At the conclusion with the record "high risk", the ratio is in the range from 1:250 to 1:380, as well as MoM indicators for one of the hormones in the range below or above the corridor of 0.5-2.5 units. Screening is considered poor.

The picture shows an example of filling out the form, the screening of the 1st trimester is given, this result is deciphered and is characterized as “Low result”, i.e., good. So we see the entry "Expected risks of trisomy" with the numbers: 21, 18, 13 - these are severe genetic diseases: Down's disease, Edward's syndrome, mental underdevelopment with hypertrichosis, but the individual numbers are very large. Which makes the risks of having a sick baby very low.

What can affect the results?

First of all, it should be noted that with twin screening results are not reliable, here the indicators can be very different, they are usually not interpreted by geneticists. This is especially true for biochemical screening for hormones (hCG and PAPP-A), the result of which is usually significantly increased.

There are a number of other factors that affect the results:

  • First of all, it is ECO. Here, the PAPP-A indicators will be changed (lower by 10-15%);
  • In addition, a condition such as pregnancy obesity will also give an increase in the level of all hormones (hCG and PAPP-A too);
  • If the weight of the pregnant woman is very low, then the level of hormones will be below normal;
  • Reduces hormonal level and diabetes;
  • It is not recommended to carry out screening of the first trimester after amniocentesis (this is a sampling for analysis amniotic fluid). Donating blood is not recommended here.
  • And also the usual fear of a pregnant woman before the procedure can affect the results. So far, fear cannot be diagnosed, and its effect on the body of a pregnant woman has not been studied. There is no way to predict the results.

What to do in case of bad tests

If the result sheet contains the phrase " high risk”, this means that the results are bad.

In this case, most likely, the pregnant woman will be asked to visit a genetics doctor. At the consultation, which will consider several options (depending on the results of the screening) further development pregnancy:

  • The first thing a doctor might recommend is to get screened in the second trimester, and then, possibly, in the third trimester.
  • In more difficult cases will be recommended (sometimes the recommendations are very urgent) invasive diagnostics. Chorionic villus biopsy, amniocentesis, or cordocentesis may be among the suggested options.
  • And based on the results of these invasive diagnostics (or one of them), the issue of prolonging the pregnancy will be considered.

Instead of conclusions

The screening procedure for the first trimester is a complex and troublesome business. But in many cases it is necessary in order to determine possible deviations in early fetal development. Sometimes this will be a signal for closer monitoring of the course of pregnancy, and in some cases a signal for action, which will help a healthy baby be born.

Unfortunately, medicine is not omnipotent and in some cases it is possible to predict the birth of a baby with chromosome disorders, but it cannot be cured, then only the pregnant woman and the father of the child will decide the fate of this pregnancy.

Sometimes 1st trimester screening is important for purely psychological reasons- he will allow the pregnant woman to overcome the fears that overcome her. And this will be the key to the health of the baby and mother, will help to get the desired peace of mind and self-confidence.

What does 1st trimester screening show? This is an ultrasound examination that helps to determine the possible presence of chromosomal diseases on early stage pregnancy. During this period, women should also undergo a blood test for and PAPP-A. If it turned out that the screening results of the 1st trimester are poor (ultrasound and blood counts), then this indicates high risk the presence of Down syndrome in the fetus.

Screening norms of the 1st trimester and their interpretation

During ultrasound, the thickness of the cervical fold in the fetus is examined, which should increase proportionally as it grows. An examination is carried out at the 11-12th week of pregnancy, and the neck fold should be from 1 to 2 mm at this time. By week 13, it should reach a size of 2-2.8 mm.

The second of the indicators of the 1st trimester screening norm is the visualization of the nasal bone. If it is not visible during the examination, then this indicates the possibility of a risk of Down syndrome in 60-80%, but it is believed that in 2% of healthy fetuses, it may also not be visualized at this time. By 12-13 weeks, the normal size of the nasal bone is about 3 mm.

In the process of conducting an ultrasound scan at week 12, the age and approximate date of birth of the child are determined.

1st trimester screening - interpretation of blood test results

A biochemical blood test for beta-hCG and PAPP-A is deciphered by translating the indicators into a special MoM value. The data obtained indicate the presence of deviations or their absence for a given gestational age. But these indicators can be influenced by different factors: the age and weight of the mother, lifestyle and bad habits. Therefore, for more exact result all data is entered into a special computer program taking into account the personal characteristics of the expectant mother. This program shows the results of the degree of risk in the ratio of 1:25, 1:100, 1:2000, etc. If we take, for example, the 1:25 option, this result suggests that for 25 pregnancies with indicators like yours, 24 children are born healthy, and only one has Down syndrome.

After the 1st trimester blood test is screened and based on all the final data received, the laboratory can issue two conclusions:

  1. Positive test.
  2. Negative test.

In the first case, you will have to undergo a deeper examination and. In the second variant additional research are not needed, and you can safely wait for the next routine screening that pregnant women undergo during the 2nd trimester.