In which phase does menstrual bleeding occur?

• A. Follicular Phase
• B. Luteal Phase
• C. Ischemic Phase
• D. Menstrual Phase

Answer: (D)

Menstrual bleeding occurs during the menstrual phase, which is a key part of the menstrual cycle. During this phase, the endometrial lining, which thickened in response to hormonal changes throughout the previous cycle, is shed. This shedding is triggered by a decline in hormone levels, primarily estrogen and progesterone, that occurs when there is no conception. The menstrual phase typically lasts between 3 to 7 days and represents the beginning of a new menstrual cycle.

The other phases listed—follicular, luteal, and ischemic—have distinct roles in the overall menstrual cycle. The follicular phase involves the maturation of ovarian follicles and the preparation of the endometrium for a potential pregnancy, while the luteal phase follows ovulation and is characterized by the presence of the corpus luteum, which produces hormones to support a possible pregnancy. The ischemic phase is a short period at the end of the luteal phase, just before menstruation begins, when the endometrial blood supply is reduced due to the drop in hormones, leading up to menstruation. However, it is during the menstrual phase that bleeding occurs as the uterus expels the lining built up during the previous cycle.