What hormone is primarily responsible for the regulation of the menstrual cycle?

• A. Progesterone
• B. Estrogen
• C. Testosterone
• D. Follicle-stimulating hormone

Answer: (B)

Estrogen is primarily responsible for the regulation of the menstrual cycle. It plays a crucial role in various phases of the cycle, including the follicular phase where it encourages the growth of ovarian follicles and the proliferation of the uterine lining.

As estrogen levels rise during the follicular phase, they trigger a surge in luteinizing hormone (LH), leading to ovulation. After ovulation, estrogen continues to support the maintenance and thickening of the uterine lining in preparation for a potential pregnancy.

While progesterone also plays a significant role in the later part of the menstrual cycle, primarily in the luteal phase to maintain the uterine lining, estrogen governs the early stages and overall regulation of the cycle's progression. Testosterone, while present in both males and females, does not influence the menstrual cycle directly. Follicle-stimulating hormone (FSH) is essential for the development of ovarian follicles but is regulated by the feedback mechanisms of estrogen and progesterone rather than serving as the principal regulator itself. Thus, estrogen's overarching influence on the cycle makes it the key hormone for its regulation.