What is the role of hormones in the menstrual cycle?

The female hormones expelled from the ovary, estrogen and progesterone, cause menstruation to start in the inner wall of the uterus due to extremely low levels of these chemicals. When adequate amounts of these hormones are secreted, the uterine wall is restored.

Follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen, and progesterone are the main hormones that control the menstrual cycle. FSH stimulates the growth of follicles in the ovary, which produce estrogen. Rising estrogen levels trigger LH surge, causing ovulation. After ovulation, the ruptured follicle transforms into the corpus luteum, which secretes progesterone. Progesterone maintains the uterine lining for potential embryo implantation. If fertilization is unsuccessful, progesterone levels fall, resulting in menstruation and the beginning of a new cycle.