What occurs to the corpus luteum if fertilization does not take place?

In the event that fertilization does not take place, the corpus luteum undergoes a process known as luteolysis, leading to its disintegration. This structure, which forms from the follicle after ovulation, is responsible for producing hormones such as progesterone and estrogen that are critical for maintaining the early stages of pregnancy.

When pregnancy does not occur, the hormonal signals that support the corpus luteum are no longer present. Specifically, the hormone human chorionic gonadotropin (hCG) is released by the developing embryo following fertilization, signaling the corpus luteum to remain functional. In the absence of fertilization, the levels of luteinizing hormone decrease, which leads to the degeneration of the corpus luteum. Consequently, it decreases in size and eventually disintegrates, ultimately resulting in a decline in hormone production. This hormonal change signals the onset of menstruation as the uterine lining sheds.

This understanding of the corpus luteum's lifecycle is crucial for appreciating the dynamics of the menstrual cycle and the hormonal regulation inherent to reproduction.