What is screening during pregnancy: how and when it is done. Is screening necessary? Is the first screening mandatory?

Screening is a study carried out comprehensively on a specific group of people, in this case, pregnant women at different stages. Screening in the first trimester includes ultrasound diagnostics and biochemical blood tests. The study is aimed at identifying possible genetic abnormalities, as well as pathologies of fetal development.

In the first trimester, screening, including routine ultrasound, is carried out at 11–13 weeks of pregnancy, which is considered the optimal period for the study. If an ultrasound is performed earlier than this period or, conversely, later, the interpretation of the results may be unreliable.

Of course, a woman can write a refusal to conduct research, even despite the order of the Ministry of Health of the Russian Federation in force since 2000, but such a decision will be extremely risky and even negligent in relation not only to her health, but also to the health of the unborn child.

First trimester screening includes two types of research:

Ultrasound diagnostics.
Biochemical blood test.

Ultrasound examination in the first trimester of pregnancy requires some preparation. To conduct the study in the usual (superficial) way, when the sensor of the device slides over the belly of the expectant mother, her bladder must be full, for which it is necessary to drink about half a liter of clean still water 1-1.5 hours before the start of the procedure, or 3– Do not urinate 4 hours before the ultrasound.

If the doctor performs the procedure transvaginally, when a special sensor of the device is inserted into the vagina, then no special preparation is required. The pregnant woman must go to the toilet before starting the procedure.

A biochemical blood test is the second stage of screening and is carried out only after an ultrasound. This condition is important, since the obtained indicators always depend on the stage of pregnancy and change every day, and the exact period can only be determined using ultrasound. This condition must be met in order to obtain a correct interpretation of the study indicators and establish compliance with the necessary standards.

At the time of taking blood for analysis, the woman must have ready-made results of the first part of the study, which will indicate the exact duration of pregnancy. If the ultrasound test procedure showed regression of the pregnancy or its fading, then there is no point in carrying out the second part of the screening.

A biochemical study requires preparation so that the doctor can obtain accurate indicators and determine their compliance with standards. Blood sampling from a vein is carried out strictly on an empty stomach.

Approximately 2-3 days before visiting the treatment room, it is necessary to: exclude from the diet sweets, smoked foods, fried and fatty foods, as well as foods that are potential allergens, for example, nuts, chocolate, citrus fruits, seafood.

Failure to comply with these conditions often leads to unreliable research results.

What can you learn from screening?

In order for the ultrasound interpretation to be reliable and informative, it is necessary to carry out the procedure no earlier than the 11th week of pregnancy, but no later than the 13th.

The position of the fetus should be comfortable for inspection and measurement. If the baby's position does not allow the ultrasound procedure, the woman is asked to turn on her side, walk around, do a few squats, or cough to get the baby to turn over.

Indicators that should be examined during an ultrasound scan in the first third of pregnancy:

Coccygeal-parietal size (CTP). The measurement is taken from the parietal point of the head to the tailbone.
Biparietal size (BPD) is the distance between the tubercles of the parietal zone.
Head circumference.
Distance from the back of the head to the frontal area.
The structure of the brain, the symmetry of the arrangement of the hemispheres, the closure of the cranium.
Thickness of the collar zone (TVP).
Heart rate (HR).
The size of the heart, as well as the largest vessels.
The length of the bones of the shoulders, thighs, lower legs and forearm.
The thickness of the placenta, its structure and location in the uterus.
The location of the umbilical cord and the number of vessels in it.
Volume of amniotic fluid.
Uterine tone.
Condition of the cervix and its internal os.

When an ultrasound is performed ahead of schedule, the doctor cannot assess the size of the nasal bone; the CTE of the fetus ranges from 33 to 41 mm, which is not enough to conduct an adequate study. Heart rate during this period ranges from 161 to 179 beats, TVP from 1.5 to 2.2 mm, and BPR is 14 mm.

Standards for deciphering indicators at this time:

At week 11, the fetal nasal bone is visible, but its size cannot always be assessed. The baby's CTE is from 42 to 50 mm, BPR is 17 mm, TVP is from 1.6 to 2.4 mm, and heart rate is from 153 to 177 beats.
At week 12, the size of the nasal bone is 3 mm or just over. CTE is in the range of 51-59 mm, BPR is 20 mm, TVP is from 1.6 to 2.5 mm, and heart rate is from 150 to 174.
At 13 weeks, the nasal bone size is more than 3 mm. CTE ranges from 62 to 73 mm, BPR is 26 mm, TVP is from 1.7 to 2.7, and heart rate is from 147 to 171 beats per minute.

Biochemical screening determines a number of important indicators, one of which is human chorionic gonadotropin β-hCG, produced by the fetal membrane. It is this hormone that allows you to determine the presence of pregnancy at the earliest stages using a special test strip.

From the beginning of pregnancy during its normal course, the level of β-hCG gradually increases, reaching its maximum value by the 12th week, after which it decreases. During the second half of the term, β-hCG levels remain at the same level.

The norm for β-hCG levels is:

Week 10: from 25.80 to 181.60 ng/ml;
week 11 from 17.4 to 130.3 ng/ml;
week 12 from 13.4 to 128.5 ng/ml;
Week 13 from 14.2 to 114.8 ng/ml.

Elevated values are observed with Down syndrome in a developing fetus or when the expectant mother has a severe form of toxicosis, as well as diabetes mellitus.

Decreased readings may indicate placental insufficiency (which is usually determined by ultrasound) or that the fetus has Edwards syndrome.

The second important indicator is protein-A (PAPP-A), which is associated with pregnancy, since this protein is produced by the placenta and is responsible for its proper functioning and development.

The following data are considered normal indicators of PAPP-A:

From 10 to 11 weeks from 0.45 to 3.73 mIU/ml;
From 11 to 12 weeks from 0.78 to 4.77 mIU/ml;
From 12 to 13 weeks from 1.03 to 6.02 mIU/ml;
From 13 to 14 weeks from 1.47 to 8.55 mIU/ml.

If the readings are below normal, this may indicate not only a threat of miscarriage, but also the presence of Edwards, Down or Cornelia de Lange syndrome in the fetus. In some cases, an increase in protein levels is observed, but this does not have significant diagnostic or clinical significance.

Calculation of MoM coefficient

This indicator is calculated based on the results of the research. Its value indicates the degree of deviation of test results from the established average norms, which range from 0.5 to 2.5 for singleton pregnancies and up to 3.5 for multiple pregnancies.

In different laboratories, when examining the same blood sample, the indicators may differ, so you cannot evaluate the results yourself; only a doctor can do this.

When calculating the coefficient, it is necessary to take into account not only the tests, but also the age of the expectant mother, the presence of chronic diseases, diabetes, bad habits, the weight of the pregnant woman, the number of fetuses developing inside, as well as how the pregnancy occurred (naturally or with the help of IVF). The risk of developing pathologies in the fetus is considered high when the ratio is below 1:380.

It is important to correctly understand the meaning of this ratio. For example, if the conclusion states “1:290, high risk,” this means that among 290 women with the same data, only one had a child with a genetic pathology.

There are situations when averages deviate from the norm for other reasons, for example:

if a woman is overweight or severely obese, hormone levels are often elevated;
with IVF, PAPP-A indicators will be lower than the general average, and β-hCG, on the contrary, will be higher;
an increase in normal hormone levels can also be observed when the expectant mother has diabetes;
for multiple pregnancies, average norms have not been established, but the level of β-hCG is always higher than during the development of one fetus.

Carrying out research in the first trimester allows us to determine the presence (absence) of many pathologies in the developing fetus, for example:

Meningocele and its varieties (pathologies of neural tube development).
Down syndrome. Trisomy 21 occurs in one case out of 700 examinations, but thanks to timely diagnosis, the birth of affected infants has decreased to 1 in 1100 cases.
Omphalocele. With this pathology, a hernial sac forms on the anterior abdominal wall of the fetus, into which part of the internal organs enters.
Edwards syndrome, which is trisomy 18. Occurs in one in 7,000 cases. It is more common in babies whose mothers are over 35 years old at the time of pregnancy. When performing an ultrasound, the fetus is observed to have an omphalocele, a decrease in heart rate, and the nasal bones are not visible. In addition, disturbances in the structure of the umbilical cord are also detected, in which instead of two arteries there is only one.
Patau syndrome, which is trisomy on chromosome 13. It is very rare, about one case per 10,000 newborns, and, as a rule, about 95% of infants with this syndrome die during the first months of life. When performing an ultrasound in these cases, the doctor notes a slowdown in the development of long bones and the brain, an omphalocele and an increase in the fetal heart rate.
Triploidy, which is a genetic abnormality characterized by a triple set of chromosomes, which is accompanied by the occurrence of many developmental disorders.
Smith-Opitz syndrome. The disorder is an autosomal recessive genetic disorder that causes metabolic disturbances. As a result, the developing fetus develops many defects and pathologies, autism, and mental retardation. The syndrome occurs in one case out of 30,000.
Cornelia de Lange syndrome, which is a genetic abnormality that causes mental retardation in the unborn child. Occurs in one case out of 10,000.
Fetal anencephaly. This developmental pathology is rare. Babies with this disorder can develop inside the uterus, but they are unable to live and die immediately after birth or later in the womb. With this anomaly, the fetus lacks the brain and bones of the cranial vault.

Screening in the first trimester allows us to identify many chromosomal diseases and developmental disorders in the unborn child in the early stages of pregnancy. Screening allows you to reduce the percentage of babies born with congenital anomalies, as well as save many pregnancies in which there is a threat of termination by taking timely measures.

Prenatal screening is a combined biochemical and ultrasound examination, consisting of a blood test to determine the level of the main pregnancy hormones and a conventional ultrasound of the fetus with the measurement of several values.

First screening or “double test” (at 11-14 weeks)

Screening includes two stages: undergoing an ultrasound and drawing blood for analysis.

During an ultrasound examination, the diagnostician determines the number of fetuses, the gestational age and takes the dimensions of the embryo: CTE, BPR, size of the cervical fold, nasal bone, etc.

According to these data, we can say how correctly the baby develops in the womb.

Ultrasound screening and its norms

Assessment of the size of the embryo and its structure. Coccygeal-parietal size (CTR)- this is one of the indicators of embryo development, the size of which corresponds to the gestational age.

KTR is the size from the tailbone to the crown, excluding the length of the legs.

There is a table of normative CTE values according to the week of pregnancy (see Table 1).

Table 1 - Norm KTE according to gestational age

An upward deviation in the size of the fetus from the norm indicates the rapid development of the baby, which is a harbinger of gestation and birth of a large fetus.

The size of the fetal body is too small, indicating:

the gestational age was initially incorrectly determined by the local gynecologist, even before the visit to the diagnostician;
developmental delay as a result of hormonal deficiency, infectious disease or other ailments in the child’s mother;
genetic pathologies of fetal development;
intrauterine fetal death (but only on condition that fetal heartbeats are not audible).

Biparietal size (BDS) of the fetal head is an indicator of the baby’s brain development, measured from temple to temple. This value also increases in proportion to the duration of pregnancy.

Table 2 - Norm of fetal head BDP at a certain stage of pregnancy

Exceeding the norm of BPR of the fetal head may indicate:

a large fruit, if the other sizes are also above normal for a week or two;
abrupt growth of the embryo, if the remaining dimensions are normal (in a week or two all parameters should level out);
the presence of a brain tumor or cerebral hernia (pathologies incompatible with life);
hydrocephalus (dropsy) of the brain due to an infectious disease in the expectant mother (antibiotics are prescribed and, with successful treatment, pregnancy is maintained).

The biparietal size is less than normal in the case of underdevelopment of the brain or the absence of some of its parts.

The thickness of the collar space (TVP) or the size of the “neck fold”- this is the main indicator that, if deviated from the norm, indicates a chromosomal disease (Down syndrome, Edwards syndrome or another).

In a healthy child, at the first screening, TVP should not be more than 3 mm (for ultrasound performed through the abdomen) and more than 2.5 mm (for vaginal ultrasound).

The value of TVP in itself does not mean anything, it is not a death sentence, it is simply a risk. We can talk about a high probability of developing chromosomal pathology in the fetus only in the case of poor results of a blood test for hormones and when the size of the cervical fold is more than 3 mm. Then, to clarify the diagnosis, a chorionic villus biopsy is prescribed to confirm or refute the presence of chromosomal pathology of the fetus.

Table 3 - TVP norms by week of pregnancy

Nose bone length. In a fetus with a chromosomal abnormality, ossification occurs later than in a healthy fetus, therefore, in case of developmental abnormalities, the nasal bone is either absent at the first screening (at 11 weeks) or its size is too small (from 12 weeks).

The length of the nasal bone is compared with the standard value from the 12th week of pregnancy; at 10-11 weeks the doctor can only indicate its presence or absence.

If the length of the nasal bone does not correspond to the period of pregnancy, but other indicators are normal, there is no cause for concern.
Most likely, this is an individual feature of the fetus, for example, such a baby’s nose will be small and snub-nosed, like his parents or one of his close relatives, for example, his grandmother or great-grandfather.

Table 4 - Normal length of the nasal bone

Also, at the first ultrasound screening, the diagnostician notes whether the bones of the cranial vault, butterfly, spine, limb bones, anterior abdominal wall, stomach, and bladder are visualized. At this stage, the indicated organs and parts of the body are already clearly visible.

Assessment of fetal vital activity. In the first trimester of pregnancy, the vital activity of the embryo is characterized by cardiac and motor activity.

Since fetal movements are usually periodic and barely distinguishable at this stage, only the heart rate of the embryo has diagnostic value, and motor activity is simply noted as “determined.”

Heart rate (HR) the fetus, regardless of gender, at 9-10 weeks should be in the range of 170-190 beats per minute, from the 11th week until the end of pregnancy - 140-160 beats per minute.

Fetal heart rate below normal (85-100 beats/min) or above normal (more than 200 beats/min) is an alarming sign, in which additional examination and, if necessary, treatment are prescribed.

Study of extraembryonic structures: yolk sac, chorion and amnion. Also, the ultrasound diagnostician in the screening ultrasound protocol (in other words, in the ultrasound results form) notes data on the yolk sac and chorion, on the appendages and walls of the uterus.

Yolk sac- this is an organ of the embryo, which until the 6th week is responsible for the production of vital proteins, plays the role of the primary liver, circulatory system, and primary germ cells.

In general, the yolk sac performs various important functions up to the 12-13th week of pregnancy, after which there is no need for it, because the fetus is already developing separate organs: liver, spleen, etc., which will take on all the responsibilities for ensuring vital functions. .

By the end of the first trimester, the yolk sac shrinks in size and turns into a cystic formation (yolk stalk), which is located near the base of the umbilical cord. Therefore, at 6-10 weeks the yolk sac should be no more than 6 mm in diameter, and after 11-13 weeks, normally it is not visualized at all.

But everything is purely individual, the main thing is that it does not complete its functions ahead of schedule, so by 8-10 weeks it should be at least 2 mm (but not more than 6.0-7.0 mm) in diameter.

If before the 10th week the yolk sac is less than 2 mm, then this may indicate a non-developing pregnancy or a lack of progesterone (then Duphaston or Utrozhestan is prescribed), and if at any time in the first trimester the diameter of the yolk sac is more than 6-7 mm, then this indicates the risk of developing pathologies in the fetus.

Chorion- This is the outer shell of the embryo, covered with many villi that grow into the inner wall of the uterus. In the first trimester of pregnancy, the chorion provides:

feeding the fetus with necessary substances and oxygen;
removal of carbon dioxide and other waste products;
protection against the penetration of viruses and infections (although this function is not durable, but with timely treatment the fetus does not become infected).

Within normal limits, the localization of the chorion is “at the bottom” of the uterine cavity (on the upper wall), on the front, back or one of the side walls (left or right), and the structure of the chorion should not be changed.

The location of the chorion in the area of the internal pharynx (the transition of the uterus to the cervix), on the lower wall (at a distance of 2-3 cm from the pharynx) is called chorion presentation.

But such a diagnosis does not always indicate placenta previa in the future; usually the chorion “moves” and is firmly fixed higher.

Chorionic presentation increases the risk of spontaneous miscarriage, so with this diagnosis, stay in bed, move less and do not overwork. There is only one treatment: lie in bed for days (getting up only to go to the toilet), from time to time raising your legs up and remaining in this position for 10-15 minutes.

By the end of the first trimester, the chorion will become the placenta, which will gradually “mature” or, as they also say, “grow old” until the end of pregnancy.

Up to 30 weeks of pregnancy – degree of maturity 0.

This assesses the ability of the placenta to provide the child with everything necessary at each stage of pregnancy. There is also the concept of “premature aging of the placenta,” which indicates a complication of pregnancy.

Amnion- This is the inner water membrane of the embryo in which amniotic fluid (amniotic fluid) accumulates.

The amount of amniotic fluid at 10 weeks is about 30 ml, at 12 weeks - 60 ml, and then it increases by 20-25 ml per week, and at 13-14 weeks it already contains about 100 ml of water.

When examining the uterus by an ophthalmologist, increased tone of the uterine myometrium (or hypertonicity of the uterus) may be detected. Normally, the uterus should not be in good shape.

Often in the ultrasound results you can see the entry “local thickening of the myometrium along the posterior/anterior wall,” which means both a short-term change in the muscular layer of the uterus due to the pregnant woman’s feeling of agitation during the ultrasound, and increased uterine tone, which is a threat of spontaneous miscarriage.

The cervix is also examined; its os should be closed. The length of the cervix at 10-14 weeks of pregnancy should be about 35-40 mm (but not less than 30 mm for primiparas and 25 mm for multiparas). If it is shorter, then this indicates the risk of premature birth in the future. Approaching the day of the expected birth, the cervix will shorten (but should be at least 30 mm by the end of pregnancy), and before the birth itself, its pharynx will open.

Deviation from the norm of some parameters during the first screening does not give cause for concern; it’s just that future pregnancies should be monitored more closely, and only after the second screening can we talk about the risk of developing defects in the fetus.

Standard ultrasound protocol in the first trimester

Biochemical screening (“double test”) and its interpretation

Biochemical screening of the first trimester involves determining two elements contained in a woman’s blood: the level of free b-hCG and plasma protein-A - PAPP-A. These are two pregnancy hormones and with normal development of the baby they should correspond to the norm.

Human chorionic gonadotropin (hCG) consists of two subunits - alpha and beta. Free beta-hCG is unique in its own way, so its value is taken as the main biochemical marker used to assess the risk of chromosomal pathology in the fetus.

Table 5 - Norm of b-hCG during pregnancy by week

An increase in the value of free b-hCG indicates:

the risk of having Down syndrome in the fetus (if the norm is twice as high);
multiple pregnancy (hCG level increases in proportion to the number of fetuses);
the pregnant woman has diabetes mellitus;
gestosis (i.e. with increased blood pressure + edema + detection of protein in the urine);
fetal malformations;
hydatidiform mole, choriocarcinoma (a rare type of tumor)

A decrease in beta-hCG value indicates:

the risk of having Edwards syndrome (trisomy 18) or Patau syndrome (trisomy 13) in the fetus;
threat of miscarriage;
fetal developmental delay;
chronic placental insufficiency.

PAPP-A– pregnancy-associated plasma protein-A.

Table 6 - PAPP-A norm during pregnancy by week

A reduced level of PAPP-A in the blood of a pregnant woman gives good reason to assume that there is a risk:

development of chromosomal pathology: Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), Patai syndrome (trisomy 13) or Cornelia de Lange syndrome;
spontaneous miscarriage or intrauterine fetal death;
fetoplacental insufficiency or fetal malnutrition (i.e., insufficient body weight due to malnutrition of the baby);
development of preeclampsia (assessed together with the level of placental growth factor (PLGF). A high risk of developing preeclampsia is indicated by a decrease in PAPP-A together with a decrease in placental growth factor.

Increased PAPP-A may occur if:

a woman is carrying twins/triplets;
the fetus is large and the placenta mass is increased;
the placenta is located low.

For diagnostic purposes, both indicators are important, so they are usually considered in combination. So, if PAPP-A is reduced and beta-hCG is increased, there is a risk of the fetus having Down syndrome, and if both indicators are reduced, there is a risk of Edwards syndrome or Patau syndrome (trisomy 13).

After the 14th week of pregnancy, the test for PAPP-A is considered uninformative.

Second screening of the second trimester (at 16-20 weeks)

II screening, as a rule, is prescribed in case of deviations in screening I, less often when there is a threat of miscarriage. If there are no abnormalities, the second comprehensive screening can be omitted, but only a fetal ultrasound can be performed.

Ultrasound screening: norms and deviations

Screening ultrasound at this stage is aimed at determining the “skeletal” structure of the fetus and the development of its internal organs.
Fetometry. The diagnostician notes the presentation of the fetus (breech or cephalic) and takes other indicators of fetal development (see Table 7 and 8).

Table 7 - Standard fetal sizes according to ultrasound

As with the first screening, the length of the nasal bone is measured in the second. If other indicators are normal, deviation of the length of the nasal bone from the norm is not considered a sign of chromosomal pathologies in the fetus.

Table 8 - Normal length of the nasal bone

According to the measurements taken, one can judge the true gestational age.

Fetal anatomy. An ultrasound specialist examines the baby’s internal organs.

Table 9 - Normative values of the fetal cerebellum by week

The dimensions of both the lateral ventricles of the brain and the cistern magna of the fetus should not exceed 10-11 mm.

Usually other indicators, such as: Nasolabial triangle, Eye sockets, Spine, 4-chamber section of the heart, Section through 3 vessels, Stomach, Intestines, Kidneys, Bladder, Lungs - in the absence of visible pathologies are marked as “normal”.

The place of attachment of the umbilical cord to the anterior abdominal wall and to the center of the placenta is considered normal.

Abnormal attachment of the umbilical cord includes marginal, shell and split, which leads to difficulties in the birth process, fetal hypoxia and even its death during childbirth, if a planned CS is not prescribed or in case of premature birth.

Therefore, in order to avoid fetal death and blood loss in a woman during childbirth, a planned caesarean section (CS) is prescribed.

There is also a risk of developmental delay, but with normal indicators of the baby’s development and careful monitoring of the woman in labor, everything will go well for both.

Placenta, umbilical cord, amniotic fluid. The placenta is most often located on the back wall of the uterus (the form may specify more on the right or left), which is considered the most successful attachment, since this part of the uterus is best supplied with blood.

The area closer to the bottom also has a good blood supply.

But it happens that the placenta is localized on the anterior wall of the uterus, which is not considered something pathological, but this area is subject to stretching as the baby grows inside the womb, plus active movements of the baby - all this can lead to placental abruption. In addition, placenta previa is more common in women with an anterior placenta.

This is not critical, just this information is important for making a decision about the method of delivery (whether a cesarean section is necessary and what difficulties may arise during childbirth).

Normally, the edge of the placenta should be 6-7 cm (or more) above the internal os. Its location in the lower part of the uterus in the area of the internal pharynx, partially or completely blocking it, is considered abnormal. This phenomenon is called “placenta previa” (or low placentation).

It is more informative to measure the thickness of the placenta after the 20th week of pregnancy. Until this time, only its structure is noted: homogeneous or heterogeneous.

From 16 to 27-30 weeks of pregnancy, the structure of the placenta should be unchanged and homogeneous.

A structure with an expansion of the intervillous space (IVS), echo-negative formations and other types of abnormalities negatively affects the nutrition of the fetus, causing hypoxia and developmental delay. Therefore, treatment with Curantil (normalizes blood circulation in the placenta), Actovegin (improves oxygen supply to the fetus) is prescribed. With timely treatment, babies are born healthy and on time.

After 30 weeks, there is a change in the placenta, its aging, and, as a result, heterogeneity. In the later stages, this is already a normal phenomenon and does not require additional examinations or treatment.

Normally, up to the 30th week, the degree of maturity of the placenta is “zero”.

The amount of amniotic fluid. To determine their quantity, the diagnostician calculates the amniotic fluid index (AFI) according to measurements taken during an ultrasound.

Table 10 - Norms of amniotic fluid index by week

Find your week of pregnancy in the first column. The second column indicates the normal range for a given period. If the AFI indicated by the ultrasound specialist in the screening results is within this range, then the amount of amniotic fluid corresponds to the norm; less than the norm means early oligohydramnios, and more means polyhydramnios.

There are two degrees of severity: moderate (minor) and severe (critical) oligohydramnios.

Severe oligohydramnios threatens abnormal development of the fetal limbs, spinal deformation, and the baby’s nervous system also suffers. As a rule, children who have suffered oligohydramnios in the womb are delayed in development and weight.

In case of severe oligohydramnios, drug treatment must be prescribed.

Moderate oligohydramnios usually does not require treatment, you just need to adjust your diet, minimize physical activity, and take a vitamin complex (it must include vitamin E).

If there are no infections, preeclampsia or diabetes mellitus in the mother of the child, and if the baby is developing within normal limits, there is no reason to worry; most likely, this is a feature of the course of this pregnancy.

Normally, the umbilical cord has 3 vessels: 2 arteries and 1 vein. The absence of one artery can lead to various pathologies in the development of the fetus (heart defects, esophageal atresia and fistula, fetal hypoxia, disruption of the genitourinary or central nervous system).

But we can talk about the normal course of pregnancy, when the work of the missing artery is compensated by the existing one:

normal results of blood tests for hCG, free estriol and AFP, i.e. in the absence of chromosomal pathologies;
good indicators of fetal development (according to ultrasound);
the absence of defects in the structure of the fetal heart (if an open functional oval window is detected in the fetus, there is no need to worry, it usually closes up to a year, but it is necessary to be observed by a cardiologist once every 3-4 months);
undisturbed blood flow in the placenta.

Babies with such an anomaly as a “single umbilical artery” (abbreviated as EAP) are usually born with low weight and can often get sick.

Up to a year, it is important to monitor changes in the child’s body; after a year of the baby’s life, it is recommended to thoroughly take care of his health: organize a proper balanced diet, take vitamins and minerals, perform immunity-strengthening procedures - all this can bring the condition of the little body in order.

Cervix and walls of the uterus. If there are no deviations, the ultrasound examination report will indicate “Cervix and walls of the uterus without features” (or abbreviated w/o).

The length of the cervix in this trimester should be 40-45 mm, 35-40 mm is acceptable, but not less than 30 mm. If there is its opening and/or shortening compared to the previous ultrasound measurement or softening of its tissues, which is generally called “isthmic-cervical insufficiency” (ICI), then the installation of an obstetric unloading pessary or suturing is prescribed to maintain the pregnancy and reach the desired term.

Visualization. Normally it should be “satisfactory”. Visualization is difficult when:

inconvenient position of the fetus for examination (the baby is simply positioned in such a way that not everything can be seen and measured, or he was constantly spinning during the ultrasound);
overweight (in the visualization column the reason is indicated - due to subcutaneous fatty tissue (SFA));
edema in the expectant mother
hypertonicity of the uterus during ultrasound.

Standard ultrasound protocol in the second trimester

Biochemical screening or “triple test”

Biochemical screening of blood in the second trimester is aimed at determining three indicators - the level of free b-hCG, free estriol and AFP.

Free beta-hCG rate look at the table below, and you will find a transcript, it is similar at each stage of pregnancy.

Table 11 - Free b-hCG rate in the second trimester

Free estriol is one of the pregnancy hormones that reflects the functioning and development of the placenta. During the normal course of pregnancy, it grows progressively from the first days of the formation of the placenta.

Table 12 – Norm of free estriol by week

An increase in the amount of free estriol in the blood of a pregnant woman is observed during multiple pregnancies or high fetal weight.

A decrease in estriol levels is observed in cases of fetoplacental insufficiency, threatened miscarriage, hydatidiform mole, intrauterine infection, adrenal hypoplasia or anencephaly (neural tube development defect) of the fetus, Down syndrome.

A decrease in free estriol by 40% or more from the normative value is considered critical.

Taking antibiotics during the test period can also affect the decrease in estriol in a woman’s blood.

Alpha fetoprotein (AFP) is a protein produced in the liver and gastrointestinal tract of the baby, starting from the 5th week of pregnancy from conception.

This protein enters the mother’s blood through the placenta and from the amniotic fluid, and begins to increase in it from the 10th week of pregnancy.

Table 13 - AFP norm by week of pregnancy

If during pregnancy a woman suffered from a viral infection and the baby suffered liver necrosis, then an increase in AFP in the pregnant woman’s blood serum is also observed.

Third screening (at 30-34 weeks)

In total, two screenings are performed during pregnancy: in the first and second trimesters. In the third trimester of pregnancy, a final monitoring of the health of the fetus is carried out, its position is examined, the functionality of the placenta is assessed, and a decision is made on the method of delivery.

For this purpose, around 30-36 weeks, an ultrasound of the fetus is prescribed, and from 30-32 weeks, cardiotocography (abbreviated as CTG - registration of changes in the cardiac activity of the fetus depending on its motor activity or contractions of the uterus).

Doppler ultrasound may also be prescribed, which allows you to assess the strength of blood flow in the uterine, placental and great vessels of the fetus. With the help of this study, the doctor will find out whether the baby has enough nutrients and oxygen, because it is better to prevent the occurrence of fetal hypoxia than to solve health problems for the baby after birth.

It is the thickness of the placenta, along with the degree of maturity, that shows its ability to supply the fetus with everything necessary.

Table 14 - Thickness of the placenta (normal)

If the thickness decreases, a diagnosis of placental hypoplasia is made. Usually this phenomenon is caused by late toxicosis, hypertension, atherosclerosis or infectious diseases suffered by a woman during pregnancy. In any case, treatment or maintenance therapy is prescribed.

Most often, placental hypoplasia is observed in fragile miniature women, because one of the factors reducing the thickness of the placenta is the weight and physique of the pregnant woman. This is not scary, what is more dangerous is the increase in the thickness of the placenta and, as a consequence, its aging, which indicates a pathology that can lead to termination of pregnancy.

The thickness of the placenta increases with iron deficiency anemia, preeclampsia, diabetes mellitus, Rh conflict and viral or infectious diseases (previous or existing) in a pregnant woman.

Normally, gradual thickening of the placenta occurs in the third trimester, which is called aging or maturity.

Degree of placenta maturity (normal):

0 degree – up to 27-30 weeks;
1st degree – 30-35 weeks;
2nd degree – 35-39 weeks;
3rd degree – after 39 weeks.

Early aging of the placenta is fraught with a deficiency of nutrients and oxygen, which threatens fetal hypoxia and developmental delays.

The amount of amniotic fluid also plays an important role in the third trimester. Below is a standard table for the amniotic fluid index - a parameter characterizing the amount of water.

Below is a table of standard fetal sizes by week of pregnancy. The baby may not correspond slightly to the specified parameters, because all children are individual: some will be large, others will be small and fragile.

Table 16 - Standard fetal sizes according to ultrasound for the entire period of pregnancy

Preparing for a screening ultrasound

Transabdominal ultrasound - the sensor is moved along the woman's abdominal wall, transvaginal ultrasound - the sensor is inserted into the vagina.

During a transabdominal ultrasound, a woman who is up to 12 weeks pregnant should come for diagnostics with a full bladder, drinking 1-1.5 liters of water half an hour to an hour before the visit to the ultrasound specialist. This is necessary so that a full bladder “squeezes” the uterus out of the pelvic cavity, which will make it possible to better examine it.

From the second trimester, the uterus increases in size and is clearly visualized without any preparation, so there is no need for a full bladder.

Bring a handkerchief with you to wipe off any remaining special gel from your stomach.

During transvaginal ultrasound, it is first necessary to perform hygiene of the external genitalia (without douching).

The doctor may tell you to purchase a condom at the pharmacy in advance, which is placed on the sensor for hygiene purposes, and to go to the toilet to urinate if the last urination was more than an hour ago. To maintain intimate hygiene, take with you special wet wipes, which you can also purchase in advance at the pharmacy or in the appropriate department of the store.

Transvaginal ultrasound is usually performed only in the first trimester of pregnancy. Using it, you can detect a fertilized egg in the uterine cavity even before the 5th week of pregnancy; abdominal ultrasound is not always possible at such an early stage.

The advantage of vaginal ultrasound is that it can detect ectopic pregnancy, the threat of miscarriage due to pathology of the placenta, diseases of the ovaries, fallopian tubes, uterus and its cervix. Also, a vaginal examination makes it possible to more accurately assess how the fetus is developing, which can be difficult to do in overweight women (with folds of fat on the abdomen).

For ultrasound examination, it is important that gases do not interfere with the examination, therefore, in case of flatulence (bloating), it is necessary to take 2 tablets of Espumisan after each meal the day before the ultrasound, and in the morning on the day of the examination, drink 2 tablets of Espumisan or a bag of Smecta, diluting it halfway glass of water.

Preparation for biochemical screening

Blood is taken from a vein, preferably in the morning and always on an empty stomach. The last meal should be 8-12 hours before sampling. On the morning of blood sampling, you can drink only mineral water without gas. Remember that tea, juice and other similar liquids are also food.

Cost of comprehensive screening

If routine ultrasound examinations in city antenatal clinics are most often carried out for a small fee or completely free of charge, then conducting prenatal screening is an expensive set of procedures.

Biochemical screening alone costs from 800 to 1600 rubles. (from 200 to 400 UAH) depending on the city and the “plus” laboratory, you also need to pay somewhere around 880-1060 rubles for a regular ultrasound of the fetus. (220-265 UAH). In total, comprehensive screening will cost at least 1,600 – 2,660 rubles. (420-665 UAH).

It makes no sense to conduct prenatal screening at any stage of pregnancy if you are not ready to have an abortion if doctors confirm that the fetus has mental retardation (Down syndrome, Edwards syndrome, etc.) or defects of any organs.

Comprehensive screening is intended for early diagnosis of pathologies in the intrauterine development of the fetus, in order to be able to produce only healthy offspring.

Throughout the entire period of bearing a baby, the expectant mother will have to undergo a number of different diagnostic tests in order to monitor the health of the woman and her fetus. Some tests are mandatory, while others are advisory. This is exactly what biochemical is, why it is performed and what pathologies can be detected with its help, we will consider in the article.

What is it like during pregnancy?

This method of diagnostic research has become widespread in medical practice quite recently. Initially, it was carried out solely according to the doctor’s indications for the purpose of early diagnosis of certain genetic pathologies. But due to its accessibility and effectiveness, this method has also begun to be used in preventive studies. Now, without special medical indications, one can undergo such a test if desired.

So, biochemical screening - what is it? This is a venous blood test to determine chromosomal pathologies. But screening results cannot be a final diagnosis; it is impossible to confirm the presence of a chromosomal disease with 100% accuracy using this method. Only the probability of such a pathology is determined in each specific case.

In order to correctly interpret the results of the biological analysis, immediately before blood sampling, the pregnant woman is sent for an ultrasound examination. So, during an ultrasound, the doctor takes measurements of the fetus and assesses its condition. Deviations from established standards, together with high rates of biochemical blood test results, may indicate the presence of a genetic pathology in the fetus. If a high level of probability of a chromosomal disease is detected in the fetus, specialists may recommend additional diagnostic procedures. For example, in this case, doctors may order an intrauterine examination of the material in order to make a final diagnosis.

Thus, only the likelihood of having a chromosomal pathology is determined by biochemical screening. What kind of analysis is this, how it is carried out, we will find out later in the article.

Indications for screening

As stated above, the study is carried out for both preventive and clinical purposes. Screening is mandatory in the following cases:

if the married couple are close relatives;
a pregnant woman suffered any infection shortly before pregnancy and immediately during the specified period;
history of frozen pregnancy, stillbirth, miscarriage, premature birth or birth of children with genetic disorders;
there are relatives in the family with chromosomal diseases;
the age of the expectant mother exceeds 35 years;
the pregnant woman took medications prohibited during pregnancy, or was exposed to X-ray and radiation radiation;
shortly before conception, the future father or mother underwent radiation therapy or an X-ray examination;
the results of an ultrasound examination of a pregnant woman are questionable, and it is recommended to conduct perinatal biochemical screening (the attending physician will tell you in detail what this is and whether such a test is dangerous for a pregnant woman).

What does the analysis determine?

Biochemical screening is carried out two or three times throughout pregnancy. And depending on the period, it can be used to diagnose various chromosomal abnormalities in the fetus:

Edwards syndrome;
Patau syndrome;
Down syndrome;
Lange syndrome;
presence of a neural tube defect.

The first three diseases have a common name such as trisomy. Biochemical screening helps doctors identify such chromosome connection abnormalities in the early stages. What kind of pathologies are these, why are they dangerous? If trisomy is present, during a biochemical blood test of a pregnant woman, laboratory assistants detect 22 pairs of normal chromosomes and one “triple” one. Depending on where exactly the pathology formed, diseases are distinguished.

First trimester screening

In medical practice, they often resort to such an analysis as biochemical screening of the 1st trimester. What is it, why is it needed and when is it carried out? For the first time, a pregnant woman encounters the concept of screening at 11-14 weeks. Such an examination includes an ultrasound, in which the doctor measures the nuchal space of the fetus, clarifies the gestational age and PPD.

After an ultrasound examination, the woman is sent by a doctor for a blood test. At this stage, human chorionic gonadotropin and PAPP protein are determined. Based on the results obtained, specialists may suspect abnormalities in the development of the fetus, including detecting a chromosomal pathology such as Down syndrome.

Biochemical screening of the 1st trimester is also called a “double test”. What it is? The study at 11-14 weeks of pregnancy acquired this name due to the fact that a blood test is performed for two specific substances: hCG and PAPP protein.

Norms of indicators for screening in the first trimester

Indicators of hCG and PAPP are influenced by external factors, such as the weight of the pregnant woman, the terrain and climate of the area of residence, the duration of pregnancy, and others. In order to adapt the norms for the majority of women, units of measurement such as MoM were developed. Biochemical screening standards are calculated in precisely these units. In order to calculate them, the results of a pregnant woman’s blood test are divided into norms established for a specific area, period and weight category of women. Thus, if the result is 0.5-2.5 MoM, then the hormone is within normal limits. But above 2.5 MoM indicates a high risk of chromosomal pathologies.

Second trimester screening

Biochemical screening has been prescribed for the 2nd trimester: what is it and why is it necessary to undergo such an examination? A second screening may be scheduled at 16-18 weeks. During such a comprehensive examination, ultrasound diagnostics will be performed, if necessary in 3D format, during which the doctor will take measurements of the fetus, assess its heartbeat and position in the uterus.

A blood test will be performed to determine three or five hormones, such as: hCG, PAPP, estriol, and inhibin. This analysis is also called a triple test.

If necessary, the expectant mother can be referred for a consultation with a geneticist, who will evaluate the screening results and make recommendations.

Third trimester screening

Screening in the third trimester is most often carried out according to doctor's indications at 32-34 weeks. During an ultrasound examination during this period, the doctor assesses the state of development of the child’s internal organs, his presentation, the presence or absence of umbilical cord entanglement, the state of the amniotic fluid and placenta. Blood is analyzed using a triple test.

Features of third trimester screening include additional diagnostic studies in the form of Doppler and CT. Using the first procedure, blood flow is assessed and determined. The second procedure determines disturbances in the functioning of the heart. These procedures are carried out in the same way as ultrasound, being absolutely safe and painless for a pregnant woman and her child.

Preparing for screening

Did your doctor recommend you undergo biochemical screening? How to take the test to get the correct results? Proper preparation for screening is an important component that determines the reliability of the results obtained. For example, if dietary recommendations are not followed during chemical reactions, laboratory assistants will only get a fatty mass, from which it will be difficult to determine anything. Therefore, the day before perinatal screening at any stage of pregnancy, you should not consume the following foods:

spicy food;
smoked meats;
fatty and fried;
chocolate;
black strong tea and coffee;
citruses.

Blood is donated on an empty stomach.

Carrying out analysis

Screening usually takes place in two stages. The first involves an ultrasound examination. Only after receiving the ultrasound results can you go for a blood test. Usually, the results of biochemical screening can be obtained only after a fairly long time - from one and a half to three weeks. In private clinics, analysis can be carried out in an accelerated time frame - up to a week.

Is screening mandatory for pregnant women? Screening is a recommendatory examination of a pregnant woman. On the one hand, thanks to such a simple and safe study, it is possible to detect serious pathologies in the baby’s development in the early stages. But at the same time, diseases determined in this way cannot be treated. In addition, the results only indicate the degree of risk for developing disorders and do not constitute a diagnosis. If abnormalities are detected, the expectant mother faces a difficult choice regarding the further development of the pregnancy. Therefore, the final decision regarding undergoing such an examination can only be made directly by the future parents.

Decoding

Deciphering biochemical screening requires professional knowledge. Only the attending physician can interpret the results. It is important to take into account and compare various factors, compare norms, and assess predisposition to genetic diseases.

The blood test is deciphered as follows:

1:10,000 is a low risk of developing pathologies;
1:1000 - average;
1:380 - high, requiring additional research.

The ratios indicate how many pregnancies a case of pathology is possible. That is, for example, at low risk, the probability of developing a chromosomal disorder is 1 in 10,000.

The first perinatal screening is a comprehensive diagnosis of the expectant mother, which is carried out even before the birth of the baby from 10 to 13–14 weeks of intrauterine development. A classic study of this kind combines only 2 main types of medical manipulations - biochemical analysis of maternal serum and ultrasound of the fetus.

Upon completion of the tests, monitoring of the obtained data will be carried out, based on a comparison of the result with the indications of the 1st trimester ultrasound screening norm. The main goal of an individual examination is the early detection of genetic pathologies in the fetus.

Indications for use

Despite the fact that primary diagnosis is carried out for many pregnant women, there are special categories of patients who are first required to undergo an ultrasound and blood test in order to exclude a danger to the life of the unborn child and their own health. This group of people includes expectant mothers who:

previously gave birth to children with any developmental disabilities;
already have a child with documented genetic pathologies;
crossed the threshold of 35–40 years;
were exposed to infectious diseases during pregnancy;
have ever suffered from excessive use of alcohol or drugs;
have a medical history with notes about the threat of spontaneous miscarriage;
are in a consanguineous union with the potential father of the baby;
for any reason, took medications prohibited for use during gestation;
know about the presence of hereditary anomalies in the family pedigree;
have experienced a stillbirth in the past;
received a diagnosis indicating the cessation of the child’s development;
demonstrate an independent desire to analyze the risk of having an infant with specific forms of the disease.

Smoking during pregnancy is the basis for mandatory screening in the first trimester

How are the results of a fetal screening ultrasound interpreted?

Ultrasound diagnostics are prescribed, as a rule, from 10–11 weeks to 13–14 weeks, since this period of obstetric period provides the first real opportunity to study the main structures of the developing baby. Week 11–12 is a special period characterized by the transformation of the embryo into a fetus.

There is a list of the most important indicators of fetal development, which formed the basis for deciphering the ultrasound report. These include: KTR, PAPP-A, heart rate, BPR, TVP, hCG, NK, etc. In order to establish an accurate prognosis for the course of pregnancy, a specialist needs to compare the personal data of his patient obtained during the first screening with the approved standards that are prescribed in the corresponding tables.

Coccyx-parietal size

CTE is one of the most important screening indicators during pregnancy. This parameter indicates the length of the embryo/fetus, which is measured from the crown (top of the head) to the coccygeal bone. If the CTE deviates from its normal range, it can be assumed that the intrauterine development of the unborn child is at risk.

According to medical observations, the numerical designation of the coccygeal-parietal size increases as the duration of pregnancy increases. Sometimes a decrease in the index in question indicates an incorrectly determined age of the fetus. In this case, we can talk about one of the varieties of the norm. In order to confirm the diagnosis, the patient should make an appointment for the 2nd ultrasound appointment.

CTE is one of the main indicators of fetal condition

Heart rate

The state of the heart rate requires regular medical monitoring, since if there are pathological processes in the baby’s body, they will be detected in time. If the anomaly is detected at an extremely early stage of its development, the likelihood of a favorable outcome will increase.

Up to 3–4 weeks, the baby’s CV rhythm coincides with his mother’s heart rate. The average value ranges from 76 to 84 beats per minute during normal functioning of a woman’s body.

Further, when the fetal cardiac structure enters a new stage of natural improvement, the number of its contractions will begin to increase evenly. Every 24 hours the value will exceed the previous “record” by approximately 2.5–3 units. So, by 8–9 weeks, the heart rate of a child developing according to the approved norm will reach 172–176 beats/min.

If, before 83–85 days of gestation, ultrasound diagnostics did not detect such dangerous phenomena as fetal deformation or complete absence of a heartbeat, then a frozen pregnancy can be excluded from the list of possible pathologies. The subsequent phases of the formation of the body are less difficult than the 12-week “Spartan marathon”.

Provided that improved and high-quality models of medical devices were used for screening, potential parents will be able to obtain a more informative description of the child’s current condition. You should not resort to 3D/4D ultrasound unless absolutely necessary. Although such modern devices can record intrauterine activity and the baby’s appearance, their dose of radiation if ultrasound is abused can negatively affect the child’s health.

Nasal bone length

Changes in the structure of the oblong nasal bone also indicate the presence of abnormalities. Studying the condition of fetuses who were diagnosed with congenital ailments, scientists came to the conclusion that a genetic failure is often expressed in the underdevelopment of the bone structures of the nose. The first screening during pregnancy to determine the length of the nasal bone (NB) is carried out no earlier than 12–13 weeks. If the doctor ordered an ultrasound session at 10-11 weeks of pregnancy, this means that he only needs to make sure that the nasal bone is present.

In medical practice, there are often significant deviations from the ultrasound ultrasound norm, which in fact turned out to be a manifestation of the individuality of the unborn child. In this case, the indicators of other tests will correspond to the standard.

Collar thickness

The main objective of the TVP study is to measure the thickness of the fold located on the back of the neck. When the main organ systems of the fetus are formed, the area of the collar space begins to fill with a special liquid, the amount of which is subjected to careful analysis.

If the indicator at the first screening exceeded a thickness of 3 millimeters, then damage to chromosomal segments can be suspected with a high degree of probability.

Study of the structure of the yolk sac

In simple terms, the yolk sac is a temporary organ that helps maintain the life of the embryo at the initial stage of its formation. From the moment of conception, this important neoplasm is several times larger in size than the size of the unborn baby.

It should be noted that screening detection of deformation of the yolk vesicle or an overestimated/lowered indicator in most cases indicates the development of a dangerous disease, for example, Down syndrome. Sometimes, under such circumstances, a frozen pregnancy is diagnosed - premature death of the embryo.

You should not neglect the 1st screening, since with its help the sonologist will be able to examine the unique structure more carefully, making appropriate conclusions about its condition. If the yolk sac is at risk of destruction, immediate medical intervention is necessary. This is due to the fact that the bubble formed only for 3–3.5 months controls many processes in the child’s body.

Its most significant functions include:

identification of extremely important protein structures involved in the construction of protective membranes for embryonic cells;
the formation of a capillary network and red blood cells, which will become the “foundation for laying” the fetal circulatory system;
temporary liver replacement;
determination of the child’s gender by delivering to him gametes produced in the cavity of the yolk sac.

This organ is also responsible for protecting the small organism from the mother’s antibodies. No matter how controversial it may sound, the cells of a woman’s immune system, like soldiers guarding human health, attack the fetus, seeing it as a potential threat - a foreign element. In order to provide the embryo with a safe living environment, the yolk sac actively secretes hormones that begin to participate in the process of lowering blood pressure, “pacifying” immune resistance and preparing the mammary glands for breastfeeding.

After 12–14 weeks, the bubble stops its activity, gradually transforming into a cyst-like inclusion localized near the umbilical cord

Location of the placenta

The location of the placenta affects the course of the upcoming pregnancy, so during a comprehensive examination a lot of time is devoted to it. According to the medical standard, this organ should not be located in the lower region of the uterus, since its abnormal structure provokes blockage of the birth canal. This common gynecological deviation is called presentation.

Detection of a disease during the first screening during early pregnancy is not always a cause for concern. In the early stages, there is still a chance to change the extremely precarious position - in the subsequent period of gestation, the uterus may rise, taking its proper place. If a favorable outcome is not observed, doctors begin to develop a detailed action plan, which implies individual indicators for a particular patient.

Biparental fetal head size

BDP is an extremely important index, which is also included in the results of the first screening. Without going into details of medical terminology, we can say that this indicator implies measuring the head along the minor axis - the distance from one temporal bone to the other. The biparental size of the fetus is of particular value, primarily due to its direct relationship to the brain, located in the cranium.

Since this organ is the main element of the central nervous system, as well as the central processor of the body system, its condition is monitored with special attention by a specialist conducting ultrasound examination.

If no suspicious signs are observed in the final screening data, then the brain develops normally. A low index indicates a deficiency in any part of the brain or a delay in its development.

Blood chemistry

After the results of ultrasound diagnostics are received, on the basis of which the actual gestational age is determined, the pregnant woman will have to undergo the final stage of the perinatal examination - blood biochemistry. Screening involves conducting 2 tests, each of which helps to identify elements of protein origin - PAPP-A and hCG.

2–3 days before the blood biochemistry of the expectant mother, it is recommended to reduce the amount of consumption of fast food, spices, nuts, fatty foods, chocolate and confectionery

PAPP-A is a special hormone (plasma protein A) responsible for the gradual and safe development of the child in the womb. Usually, indicators about its content are determined only from 12–13 weeks, however, as an exception, the blood sampling procedure is carried out a little earlier.

Human chorionic gonadotropin is also a hormone that, unlike protein A, begins to be produced immediately after conception. It is noteworthy that its amount actively reaches its maximum value at 11–12 weeks, then the level of hCG gradually decreases, fixing at a stable level.

As soon as the patient undergoes perinatal screening in full, doctors will begin to compare the identified indices with the norm, drawing up a full final conclusion.

What pathologies can be detected during the first screening?

With the help of a comprehensive study in the first trimester, one can discover a fairly impressive list of pathologies that cause complications of varying severity, ranging from deformation of an organ to the death of the baby. The most frequently identified ailments include:

hydrocephalus;
glioma;
Down syndrome;
cerebral hernia;
astrocytoma;
Shershevsky-Turner syndrome;
omphalocele;
aneurysm;
Patau syndrome;
bradycardia;
meningocele;
intrauterine infection;
Edwards syndrome;
hypoxia;
tachycardia;
Smith-Opitz syndrome;
developmental delay;
anemia;
hemimelia (underdevelopment of the limbs);
Cornelia de Lange syndrome;
heart disease.

Only a doctor has the right to diagnose the above congenital diseases, since interpretation of an ultrasound performed by the patient independently may be done incorrectly. Forming a diagnosis based on the indicators of the first screening implies a comprehensive qualitative analysis of all data obtained, taking into account every aspect and pitfall. That is why expectant mothers are advised to trust their health and the life of their baby only to a professional. Constructive unity between the patient and the attending physician increases the likelihood of having a healthy child.

The first screening examination is prescribed to detect fetal malformations, analyze the location and blood flow of the placenta, and also to determine the presence of genetic abnormalities. Ultrasound screening of the 1st trimester is carried out at 10-14 weeks exclusively as prescribed by a doctor.

What is an ultrasound scan in the first trimester?

Ultrasound examinations take place in specially equipped private clinics or antenatal clinics, which have appropriate professionals who can carry out the necessary diagnostics.

Ultrasound screening of the 1st trimester will help to conduct a full examination at a short stage of pregnancy. The attending physician will explain how the study is carried out, and if necessary, he will also tell you how to prepare for the diagnosis.

PAPP-A is a plasma protein A associated with pregnancy. A proportional increase in this indicator indicates a normal pregnancy. Deviation from the norm indicates the presence of pathologies in fetal development. However, this only applies to a decrease in the concentration of the indicator in the blood of less than 0.5 MoM; exceeding the norm by more than 2 MoM does not pose any danger to the development of the baby.

1st trimester screening: interpretation of ultrasound results and test for the risk of developing pathologies

Laboratories have special computer programs that, based on individual indicators, calculate the risk of developing chromosomal diseases. Individual indicators include:

age;
presence of bad habits;
chronic or pathological diseases of the mother.

After entering all the indicators into the program, it will calculate the average PAPP and hCG for a specific stage of pregnancy and calculate the risk of developing anomalies. For example, a ratio of 1:200 indicates that out of 200 pregnancies a woman will have 1 child with chromosomal abnormalities, and 199 children will be born completely healthy.

A negative test indicates a low risk of developing Down syndrome in the fetus and does not require any additional tests. The next examination for such a woman will be an ultrasound

Depending on the obtained ratio, a conclusion is given in the laboratory. It can be positive or negative. A positive test indicates a high probability of having a child with Down syndrome, after which the doctor prescribes additional tests (amniocentesis and chorionic villus biopsy) to make a final diagnosis.

Ultrasound screening of the 1st trimester, reviews of which allow a woman to understand more about the results obtained, should not always be taken seriously, because only a doctor can correctly decipher the protocol.

What should you do if you are at high risk of developing Down syndrome?

If you detect a high risk of having an unhealthy child, you should not immediately resort to extreme measures to terminate the pregnancy. Initially, you need to visit a geneticist who will conduct all the necessary studies and accurately determine whether the child is at risk of developing chromosomal abnormalities.

In most cases, genetic testing disproves the presence of problems in the child and therefore the pregnant woman can safely bear and give birth to the child. If the examination confirms the presence of Down syndrome, then the parents must independently decide whether to continue the pregnancy or not.

What indicators can influence the results obtained?

When a woman is fertilized using IVF, the indicators may differ. The concentration of hCG will be exceeded, at the same time PAPP-A will be reduced by approximately 15%, and an ultrasound examination may reveal an increase in LZR.

Weight problems also greatly affect hormone levels. With the development of obesity, hormone levels increase significantly, but if body weight is excessively low, hormones will also be reduced.

The pregnant woman’s worries associated with worries about the correct development of the fetus can also affect the results obtained. Therefore, a woman should not set herself up for negativity in advance.

Can a doctor insist on an abortion if Down syndrome is detected in the fetus?

No doctor can force you to terminate a pregnancy. The decision to continue the pregnancy or terminate it can only be made by the parents of the baby. Therefore, it is necessary to carefully think through this issue and determine the pros and cons of having a child with Down syndrome.

Many laboratories allow you to see a three-dimensional picture of a child's development. Ultrasound screening photo of the 1st trimester allows parents to forever preserve the memory of the development of their long-awaited baby.