What role does progesterone play in a woman's menstrual cycle?

• A. It stimulates follicle production
• B. It prepares the endometrium for possible implantation of an embryo
• C. It induces menstruation
• D. It regulates estrogen levels

Answer: (B)

Progesterone plays a crucial role during the luteal phase of the menstrual cycle, where it prepares the endometrium (the inner lining of the uterus) to receive a fertilized egg. After ovulation, the ruptured follicle transforms into the corpus luteum, which secretes progesterone. This hormone thickens the endometrial lining, making it more receptive for a potential implantation of an embryo, thereby supporting the early stages of pregnancy.

If fertilization does not occur, the corpus luteum degenerates, leading to a drop in progesterone levels, which in turn triggers menstruation. This process emphasizes the importance of progesterone in creating a suitable environment for implantation. The hormone does not stimulate follicle production, induce menstruation directly, or regulate estrogen levels, although its interactions are critical in the overall hormonal balance during the menstrual cycle. Therefore, its role in preparing the endometrium for implantation is fundamental to reproductive physiology.