What happens to the corpus luteum if fertilization does not occur?

The corpus luteum plays a crucial role in the menstrual cycle. If fertilization does not occur, the corpus luteum does not receive the hormonal signals necessary to maintain its function. As a result, it undergoes a process called luteolysis, during which it degenerates. This degeneration leads to a decrease in the levels of progesterone and estrogen produced by the corpus luteum, which are essential for maintaining the uterine lining. Once these hormone levels drop significantly, it triggers the shedding of the uterine lining, resulting in menstruation. Thus, the correct response highlights the natural progression of the menstrual cycle when pregnancy does not take place.