Human chorionic gonadotropin is a protein that contains two particles, alpha and beta. The first of them, in structure and functions, resembles some pituitary hormones, which regulate the synthesis of hormones by the ovaries and thyroid gland. The beta particle has a unique structure.
HCG produces chorionic villus cells after the egg attaches to the wall of the uterus, a few days after fertilization. Some of these cells are required for the normal development of the fetus, and another part is required for attachment to the uterus. HCG also suppresses the aggressive reaction of the pregnant woman’s immune system directed against the cells of the fetus, participates in the sexual determination of the fetus, and activates the gonads and adrenal glands of the developing fetus.
When studying this hormone, two types of tests are taken:
1. For total hCG. The study is intended for early diagnosis of pregnancy, when standard test strips cannot yet detect pregnancy because the pregnancy is too early. If pregnancy develops normally, in the first weeks hCG doubles every 2 days and reaches its maximum concentration at 10-11 weeks. After this, hormone levels gradually decrease. If the pregnancy is multiple, the level of human chorionic gonadotropin increases in proportion to the number of fetuses.
2. For free b-hCG. This analysis is carried out to diagnose neoplasms (hydatidiform mole, testicular oncology, choriocarcinoma). The test is also performed during screening of the first and second trimesters to assess the risk of Down and Edwards syndromes in the fetus. Analysis for free b-hCG is carried out at 8-13 and 15-20 weeks of pregnancy.