HCG refers to human chorionic gonadotropin, which normally can’t grow up once it drops in early pregnancy. If human chorionic gonadotropin levels drop in early pregnancy, it usually means that the embryo is underdeveloped, has stopped, or has been miscarried. Human chorionic gonadotropin is a glycoprotein secreted by the trophoblast cells of the placenta. Chorionic gonadotropin levels increase with each week of pregnancy, so it is possible to check the rate of increase of human chorionic gonadotropin in early pregnancy to determine whether the fetus is developing normally. If the blood HCG drops in early pregnancy, it is recommended to go to the hospital as soon as possible to assess the development of the embryo. If the development has stopped and there is still a residual embryo in the uterus, it is necessary to terminate the pregnancy as soon as possible.