What is the significance of human chorionic gonadotropin (hCG) in pregnancy?

Human chorionic gonadotropin (hCG) plays a critical role in maintaining pregnancy, particularly during the early stages. After fertilization and implantation, the developing embryo produces hCG, which signals the corpus luteum to continue producing progesterone. This hormone is essential for maintaining the uterine lining, creating a supportive environment for the embryo as it develops. Without sufficient levels of progesterone, the uterine lining would shed, potentially leading to a miscarriage. Therefore, hCG is vital for the preservation of the pregnancy and its role in supporting fetal development in the initial months before the placenta takes over hormone production.