Chorionic Gonadotropin Alpha Polypeptide (CGa)

Human chorionic gonadotropin (hCG) is a glycoprotein hormone produced in pregnancy that is made by the developing embryo soon after conception and later by the syncytiotrophoblast (part of the placenta).

Its role is to prevent the disintegration of the corpus luteum of the ovary and thereby maintain progesterone production that is critical for a pregnancy in humans. hCG may have additional functions; for instance, it is thought that hCG affects the immune tolerance of the pregnancy. Early pregnancy testing, in general, is based on the detection or measurement of hCG. Because hCG is produced also by some kinds of tumor, hCG is an important tumor marker, but it is not known whether this production is a contributing cause or an effect of tumorigenesis.