Human chorionic gonadotropin, or HCG for short, is the most commonly used early pregnancy test after conception, and a positive HCG value generally indicates that a woman is pregnant. However, it should be noted that trophoblastic diseases (e.g., hyperemesis gravidarum, malignant hyperemesis gravidarum, chorionic epithelial cell carcinoma, etc.) are also positive for HCG. Serum human chorionic gonadotropin is a glycoprotein secreted by the trophoblast cells of the placenta. After fertilization, the egg moves into the uterine cavity and deposits to form an embryo. During development and growth into a fetus, placental syncytiotrophoblast cells can produce large amounts of HCG. The main role of serum human chorionic gonadotropin is to maintain the secretory function of the ovarian corpus luteum in the first few weeks of pregnancy to support the needs of early embryonic development and placental maturation; to maintain the lifespan of the menstrual corpus luteum; to protect the embryo from maternal lymphocyte attack; and to promote the development of fetal masculinity. However, it should be noted that ectopic pregnancies and trophoblastic diseases (e.g., hyperemesis gravidarum, malignant hyperemesis gravidarum, chorionic epithelial cell carcinoma, etc.) are also positive for HCG. Women with abnormal serum human chorionic gonadotropin values are advised to consult a doctor in time to determine the exact cause, so as not to delay their condition.