What is the role of FSH in the female menstrual cycle?

Follicle-stimulating hormone (FSH) plays a critical role in the female menstrual cycle primarily by promoting the development of ovarian follicles. During the first phase of the menstrual cycle, known as the follicular phase, FSH is secreted by the anterior pituitary gland in response to signals from the hypothalamus. This hormone stimulates the growth and maturation of ovarian follicles, each containing an egg.

As the follicles develop, they produce estrogen, which contributes to the thickening of the uterine lining in preparation for a potential pregnancy. The rise in estrogen levels eventually leads to a surge in luteinizing hormone (LH) that triggers ovulation, when a mature egg is released from its follicle. Therefore, FSH is essential for initiating and supporting the early stages of the menstrual cycle through follicle development, setting the stage for subsequent hormonal events and potential fertilization.