What hormone does human chorionic gonadotropin (hCG) primarily stimulate?

Human chorionic gonadotropin (hCG) is primarily known for its role in maintaining pregnancy. One of its critical functions is to stimulate the corpus luteum, which is formed from the follicle that released the egg after ovulation. The corpus luteum produces important hormones, primarily estrogen and progesterone, which are essential for sustaining the early stages of pregnancy.

By promoting the production of these hormones, hCG helps support the uterine lining and provides the necessary environment for a fertilized egg to implant and develop. This is why the presence of hCG is a key marker in pregnancy tests—its levels rise significantly during early pregnancy as the body relies on it to maintain hormonal balance until the placenta takes over hormone production later in pregnancy.

In contrast, the other choices do not relate directly to the primary role of hCG. Insulin regulation is primarily managed by the pancreas, while milk production is regulated by prolactin in the context of lactation. Thyroid hormones are not directly influenced by hCG either; instead, they are regulated by thyroid-stimulating hormone (TSH) from the pituitary gland. Therefore, the correct answer highlights the essential function of hCG in stimulating the corpus luteum for estrogen and progester