What is the primary regulator of the menstrual cycle?

• A. Testosterone
• B. Follicle-stimulating hormone (FSH)
• C. Estrogen and progesterone
• D. Luteinizing hormone (LH)

Answer: (C)

The primary regulator of the menstrual cycle is indeed a combination of estrogen and progesterone. These hormones play a crucial role in controlling the various phases of the menstrual cycle.

Estrogen is involved in the development and maturation of the ovarian follicles and the thickening of the endometrial lining during the follicular phase. It also contributes to the process that leads to ovulation. After ovulation, progesterone is produced by the corpus luteum and is essential for preparing the endometrium for potential implantation of a fertilized egg. If pregnancy does not occur, progesterone levels drop, leading to the shedding of the endometrial lining and the onset of menstruation.

While Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH) are important in regulating the menstrual cycle by stimulating the ovaries to produce eggs and hormones, they are not the primary regulators in the sense of direct effects on the menstrual phases. Instead, FSH and LH facilitate the actions of estrogen and progesterone, making them critical support hormones rather than the main regulators.

Thus, the combined actions of estrogen and progesterone truly govern the cycle, influencing everything from ovulation to the menstrual phase, making this combination the central mechanism of regulation