Prenatal diagnosis

Disturbance of the metabolism of phenylalanine refers to a very common congenital metabolic disorder. Due to the defect of the phenylalanine hydroxylase gene (phage gene), the enzyme deficiency develops, and as a result, the block enters the normal conversion of phenylalanine to the amino acid tyrosine.

17-Hydroxyprogesterone serves as a substrate for the synthesis of cortisol in the adrenal cortex. With congenital hyperplasia of the adrenal cortex or adrenogenital syndrome as a result of mutations in the genes responsible for the synthesis of various enzymes of certain stages of steroidogenesis, the content of 17-hydroxyprogesterone in the fetus, amniotic fluid and blood of the pregnant woman increases.

Estriol - the main steroid hormone, synthesized by the placenta. In the first stage of the synthesis, which takes place in the embryo, the cholesterol produced de novo or coming from the pregnant woman's blood turns into pregnenolone, which is sulphated by the adrenal cortex of the fetus in DHEA, then fetal liver turns into α-hydroxy-DHEAS, and then into estriol in placenta.

Elevated levels of chorionic gonadotropin in the serum are detected already on the 8th-9th day after conception. During the first trimester of pregnancy, the concentration of the chorionic gonadotropin rapidly rises, doubling every 2-3 days.