During which phase of the menstrual cycle does FSH stimulate egg development?

• A. Luteal phase
• B. Follicular phase
• C. Menstrual phase
• D. Ovulation phase

Answer: (B)

The follicular phase is the correct choice because it is during this phase that follicle-stimulating hormone (FSH) plays a crucial role in stimulating the growth and maturation of ovarian follicles, which contain the eggs. In the early part of the menstrual cycle, typically days 1-14, FSH is secreted by the pituitary gland. This hormone encourages several follicles to mature in the ovaries, but usually only one follicle becomes the dominant one that will release an egg during ovulation.

In contrast, during the luteal phase, which follows ovulation, the focus shifts to the maintenance of the corpus luteum and the preparation of the uterine lining for potential implantation. The menstrual phase involves the shedding of the uterine lining when pregnancy does not occur, and the ovulation phase, occurring around the midpoint of the cycle, refers to the release of the egg rather than its development. Thus, it is specifically the follicular phase where FSH's role in egg development is most prominent.