How many weeks 2 are screening for pregnancy?

This type of diagnostic examination, like screening, has relatively recently begun in the post-Soviet countries. However, due to its high informative and uncomplicated research manipulations, it has now become widely used. With the help of this survey, doctors manage to establish risk groups for the development of possible complications not only for gestation itself, but also for the development of the baby. Consider the screening in more detail and find out how many weeks during pregnancy the 2nd such research is conducted.

When is it usually re-screened?

To begin with, it must be said that for the first time a woman undergoes such a study at a very short time, 12-13 weeks. At this time, doctors manage to establish violations in the development of organs and systems. If we talk about how many weeks do the 2 screening, then the optimal time for it is 16-20 weeks. Usually it is prescribed in the interval of 17-19 weeks. It is these terms that doctors call when answering the question of expectant mothers about how many weeks during pregnancy they make a second screening.

What is the purpose of this study and what does it allow to establish?

Screening allows you to identify among women at risk of developing a chromosomal abnormality in their baby. In this case, such a procedure is always complex and includes ultrasound, a biochemical blood test. It is during the last survey that certain markers are established, among them: alpha-fetoprotein (AFP) , free estriol, human chorionic gonadotropin (hCG). In this regard, quite often from physicians you can hear the second name - triple test.

The establishment of a concentration in the blood of a pregnant woman of the substances listed above makes it possible to speak with high probability of an increased risk of the formation of such pathologies as:

• Down's syndrome (the second name is trisomy 21);
• Edwards' syndrome (trisomy 18);
• defects of the neural tube (spinal cord and anencephaly free, no brain).

How is the interpretation of the results obtained?

Having dealt with the number of weeks in which 2 screening is done, we will describe how the results are evaluated.

To begin with, it is necessary to say that only a doctor can do this. After all, changing a particular indicator is not a direct violation, but only indicates the likelihood of its development.

For example, an increase in the concentration of hCG in the blood of a future mother may indicate a greater likelihood of developing chromosomal abnormalities in a future baby, the possibility of gestosis. The decrease in the level of this hormone, as a rule, indicates a violation of the development of the placenta.

The discrepancy between the concentration of AFP in the blood serum of a future mother is regarded as a sign of a violation of the number of chromosomes, the genome of the future baby. Possible diseases that develop in this case are listed above. It should be noted that a sharp increase in the concentration of alpha-fetoprotein can cause fetal death.

The change in the concentration of free estriol serves as a signal for disrupting the work of the fetoplacental system. This allows at early stages of gestation to detect such a violation as fetal hypoxia and respond in a timely manner to it. Otherwise, the probability of disrupting the development of brain structures is great.

Thus, as can be seen from the article, screening refers to those studies that can only indicate the possibility of developing a particular pathology. Therefore, always after the evaluation of the results and the presence of suspicions, additional diagnostics are prescribed.