Which hormone is primarily responsible for regulating the menstrual cycle?

The hormone primarily responsible for regulating the menstrual cycle is estrogen. Estrogen plays a crucial role in the development and regulation of the female reproductive system and secondary sexual characteristics. During the menstrual cycle, estrogen levels fluctuate, influencing the growth and maintenance of the endometrial lining in preparation for a potential pregnancy.

In the first half of the cycle, estrogen helps stimulate the maturation of the ovarian follicles and promotes the thickening of the uterine lining. As ovulation approaches, estrogen levels peak, triggering a surge in luteinizing hormone, which ultimately leads to ovulation. After ovulation, estrogen, along with progesterone, helps to maintain the uterine lining during the luteal phase.

While progesterone, luteinizing hormone, and follicle-stimulating hormone are also important in the menstrual cycle, their roles are more specific. Progesterone primarily supports the endometrial lining after ovulation, luteinizing hormone is critical for triggering ovulation, and follicle-stimulating hormone is essential for stimulating follicle development early in the cycle. Estrogen, however, is the primary regulator throughout the entire cycle, making it the most influential hormone in coordinating the various phases of the menstrual cycle.