Choriogonadotropin

Human chorionic gonadotropin (hCG) together with lutropin (LH), follitropin (FSH) and thyreotropin (TSH), belongs to the group of glycoprotein hormones. Unlike other glycoprotein hormones produced in the adenohypophysis, hCG is produced by the syncytiotrophoblast of the placenta during pregnancy. It stimulates the growth of the corpus luteum, which forms estrogens and progesterone. Chemically, hCG consists of two subunits - alpha and beta. The alpha subunits of all glycoproteins are identical, the biological specificity of these hormones is therefore determined by the beta subunits.

The presence of hCG in a woman's blood or urine is evidence of pregnancy and helps to monitor its progress. A value lower than the normal limit of hCG is a sign of an ectopic pregnancy, stillbirth or impending abortion. In contrast, elevated hCG levels signal multiple pregnancies and allow early diagnosis of trisomy 21 - Down syndrome (along with AFP and uE3 assays). HCG production increases rapidly in early pregnancy. We record the maximum growth between the 80th and 90th day of pregnancy, then its production decreases (at 4 months), and after the 25th week the hCG value remains stable until delivery. Its urinary excretion ends about the 7th day after delivery, i.e. after expulsion of the fetus and placenta.