Which hormone is produced by the corpus luteum?

The hormone produced by the corpus luteum is progesterone. After ovulation, the ruptured follicle transforms into the corpus luteum, which plays a critical role in maintaining early pregnancy. The primary function of progesterone is to prepare the uterine lining for a potential implantation of a fertilized egg. It thickens the endometrium and helps maintain its readiness for embryo implantation. If pregnancy does not occur, the corpus luteum degenerates, leading to a drop in progesterone levels, which signals the beginning of menstruation.

In contrast, estrogen is also produced during this phase but primarily by the growing follicles before ovulation, while testosterone is primarily produced in the testes. Follicle-stimulating hormone, on the other hand, is secreted by the pituitary gland and does not relate directly to the function of the corpus luteum. The significance of progesterone in reproductive health and its role in the menstrual cycle makes it the correct answer in this context.