Screening during pregnancy: terms of conduct, results. When, in what week of pregnancy is the first, second and third screening during pregnancy? Decoding 1, 2, 3 of screening during pregnancy: Norm

Even 20 years ago, doctors could hardly determine the gender of the child. The presence of any pathologies of the fetus was not discussed at all, since then there were no screening, which became mandatory since 2000.

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What shows screening during pregnancy?

Screening-a study of the number of hormones and conducting an ultrasound by which you can find out if the child has any genetic deviations. Simply put, doctors will find out if there is a defect in the nerve tube in the fetus or Down syndrome. It is also possible to learn about the possibility of other serious deviations.

In total, a woman is doing three screening for pregnancy. Each of them includes a biochemical test of blood, ultrasound and analysis for the amount of hormones. According to these results, even in the early stages, it is possible to determine the presence of genetic disorders in the child. A woman is given a choice whether to give birth to a sick baby or not.

Unfortunately, now there is a very large number of false and positive results, when screening shows the presence of deviations that are actually not. In this case, the pregnant woman is offered to conduct an invasive research method.

How many screening is done for pregnancy?

Three screening are approved, but the doctor according to indications may prescribe additional studies. Usually they are associated with impaired pregnant health. Do not be surprised if you are asked to pass a few tests of blood, urine and strokes.

Only two ultrasound are approved, at 11-12 weeks and at 20-24 weeks. The rest are only according to the indications. But doctors are often reinsured and prescribed an ultrasound at 32 weeks. This is in order to determine the presentation of the fetus and its size. The amount of water and the development of all organs of the baby are also determined.

How many weeks of pregnancy do the first screening do?

The first screening is done at 11-12 weeks of pregnancy. At this time, such research is conducted:

Ultrasound. This study is carried out in order to determine the exact gestational age and the presence of developmental abnormalities in the fetus. At this time, they measure the thickness of the collar space. With indicators more than 2 mm, additional studies are prescribed.
Blood test for hCG and RARR-A. These indicators will allow you to determine if there are an anomalies of development in the fetus and how the pregnancy proceeds well. This test is called double.
Analysis of urine and blood. For registration, it is necessary to take a lot of analyzes. These are studies for HIV, syphilis and genital infections. Often women consider these studies the first screening, but in fact it is not. Typically, registration coincides with the first screening.

Decoding the first screening during pregnancy

At this time, the size of the child, the length of the bones of the arms and legs, and the size of the abdomen are determined on the ultrasound. These indicators can vary widely, and little talk about.

Decoding of screening:

It is worth paying attention to the thickness of the collar space. With indicators above 2 mm, a woman is prescribed a second ultrasound. The exact date of pregnancy is of great importance. At 13 weeks, TVP may not be higher than 2.7 mm
Ktr. This is the size of the child from the crown to the tailbone. At 10 weeks it is 14 mm, and at 13 weeks already 26 mm
HCG. This is a hormone that stands out during pregnancy, by its number we can judge the pathologies of the fetus. For example, a large amount of hCG speaks of multiple pregnancy, gestosis or pathologies of fetal development. Often, the level of this hormone increases when taking progestins (Urostar, Duphaston). With low values \u200b\u200bof the hCG, the doctor can suspect an ectopic or frozen pregnancy. With a high hCG, the baby can suspect Down syndrome, and with low indicators - Edwards syndrome. Read more in the table
Content of the RARR-A. The increased content of this hormone also indicates pathologies in the development of the fetus and chromosomal disorders

What week of pregnancy is the second screening?

The norm is considered 16-22 weeks. Doctors recommend donating blood from 16 to 18 weeks. At this time, a triple test is carried out. It reflects the amount of AFP, hCG and free estriol. Based on the results of studies, one can judge the presence of chromosomal disorders of the fetus, as well as possible diseases of internal organs.

Ultrasound is recommended to be done a little later, from 20-24 weeks. At such a period, you can see the dimensions of the internal organs of the fetus and their compliance with the gestation period.

Decoding and norms of the second screening

With the results of the tests, you will receive not only the content of three hormones in the blood, but also their norms. They may differ in different laboratories depending on the research method.

In general, on the second screening, all indicators are considered in the complex. The increased or reduced content of a particular hormone does not mean anything. So, with high hCG and low AFP there is a high risk of a child with Down syndrome. In this case, the high value of the hCG with a normal concentration of AFP may indicate the use of hormonal drugs of the pregnant woman.
In many laboratories, after a triple test, a graph is built. Based on its meanings, you will be given the risk of developing pathologies for the fetus and Down syndrome.
Free Estriol is a hormone that is produced by the adrenal glands of the fetus and placenta. With a decrease in the value by 40%, we can talk about the pathologies of the internal organs of the fetus or overstraging the child.
See the picture of normal estriol in the picture below.

What week do I do the third screening?

This screening no longer requires blood donation for hormones if pathologies are not detected according to the results of previous screening. Such a diagnosis is carried out with 32-36 weeks. During the ultrasound, the doctor carefully studies the condition and dimensions of the internal organs of the fetus. In addition, a child’s blood flow is carried out.

More precisely, the doctor looks at the main veins and blood vessels of the child and his heart. It helps to find out if the baby is enough. If you have everything normal after 1 and 2 screening, the doctor does not prescribe a blood test for hormones. Only with dubious results of previous screening will you get a direction.

Decoding and norms of the third pregnancy screening

The purpose of the third screening is to find out the development of the pathology of the fetus, as well as determine the state of the placenta.

Here are the norms of the main indicators of the fetus:

LZR (Lobno-Treaty) from 102 to 107 mm
BPR (biparier) on average from 85 to 89 mm
Og from 309 to 323 mm
OZH from 266 to 285 mm
the size of the forearm is from 46 to 55 mm
bone size of the lower leg from 52 to 57 mm
thigh length from 62 to 66 mm
shoulder length from 55 to 59 mm
child growth from 43 to 47 cm
fetal weight from 1790 to 2390 grams

Screening for multiple pregnancy

At the first screening, a woman who wears several babies will be prescribed an ultrasound. When confirming multiple pregnancy, tests for hCG and RARR-A are not prescribed.

With multiple pregnancy, these results are dubious and are not informative.
On the first ultrasound to detect anomalies in the development of the fetus, the TVP is evaluated for both fruits and the presence of free fluid in the cervical space.
From 16 to 20 weeks, a blood test for hormones, that is, triple, the test also does not make sense to pass. These results are inaccurate and cannot indicate the health or vices of the child.

The only reliable study with multiple pregnancy is ultrasound.

When to screening during pregnancy: tips

In order not to miss the screening date, it is necessary to account for the gynecologist until 12 weeks. He will sign it by the days of what and when to go.

Complete screening in the indicated time framework. The first screening takes place better at 11-12 weeks. It is at this time that the results of the double test are the most accurate.
The second screening should be carried out from 16-18 weeks (this is a triple test). Ultrasound should be done later at 20-24 weeks. You need to come to the doctor with the results of triple dough with the first ultrasound. Reconciliation of the results and the identification of possible risks is carried out.
Be sure to warn the doctor about taking medication. Do not eat anything before blood donation. A few days before screening, do not eat chocolate and seafood.