Serum human chorionic gonadotropin is a glycoprotein hormone, consisting mainly of alpha and beta subproteins, produced mainly by gestational trophoblast cells. Patients can produce blood chorionic gonadotropin after pregnancy or in other pathological states, such as gestational trophoblastic disease, reproductive tract tumors, and tumors of the lung, adrenal gland, or liver. In clinical practice, chorionic gonadotropin is most commonly used to monitor a patient’s pregnancy and the development of the gestational sac during pregnancy. Normally, chorionic gonadotropin is produced by the trophoblast layer of the fertilized egg on the sixth day after ovulation, and elevated levels of chorionic gonadotropin can be detected in the peripheral blood approximately one day later. The level of chorionic gonadotropin doubles every 1.7-2 days, reaching 100 U/L on the 14th day of ovulation and peaking at about 50-100,000 U/L by 8-10 weeks of pregnancy.