A-fetoprotein in serum

In the second trimester of pregnancy, in the presence of Down syndrome in the fetus, the concentration of AFP in the serum of a pregnant woman is lowered, and the concentration of

HG is increased. With this in mind, the study on AFP and HG is used as a method of mass prenatal examination of pregnant women, with the help of which it is possible to identify a group of high risk for the presence of fetal malformations or Down's syndrome. The median values ​​of serum AFP concentrations for screening of congenital malformations in the II trimester are given in Table 1.

Table Median AFP concentration values ​​in serum for screening of congenital malformations in the 2nd trimester

Table Median AFP concentrations in serum for screening for congenital malformationsdevelopment in the II trimester

The main hereditary diseases in which changes in the concentration of AFP in the blood are revealed are presented in Table. .

Table Hereditary diseases,accompanied by a change in the concentration of AFP

Table Hereditary diseases accompanied by a change in the concentration of AFP

FREE ESTRIOL IN THE BLOOD SERUM

Estriol is the main steroid hormone synthesized by the placenta. In the first stage of the synthesis that takes place in the embryo, the cholesterol de novo formed from the blood of the pregnant woman is transformed into pregnenolone, which is sulfated by the adrenal cortex of the fetus in DHEA, then in the fetal liver is converted to a-hydroxy-DHEA, and then to estriol inplacenta. As a rule, the content of estriol in the pregnant woman's blood is correlated with the activity of the adrenal glands of the fetus. Estriol penetrates into the bloodstream of a pregnant woman, where it is possible to determine the concentration of its unconjugated form. With a normally developing pregnancy, the production of estriol increases in accordance with the increase in gestation and fetal growth( Table).

In the case of pathology( expressed malformations of the central nervous system in the fetus, congenital heart disease, Down's syndrome, fetal growth retardation, fetal adrenal hypoplasia, fetal fetal death), the concentration of free estriol in the serum of the pregnant woman decreases.

With Down's syndrome and Edwards, the concentration of free estriol is usually 0.7MoM.

Table Concentration of estriol in serum in the dynamics of physiological pregnancy

Table Concentration of estriol in serum in the dynamics of physiological pregnancy

Median concentrations of free estriol in serum for screening of congenital malformations in the second trimester are given in Table. .

Table Median concentrations of freeestriol in serum for screening of congenital malformations in the 2nd trimester of pregnancy