Which statement about progesterone is correct?

• A. It promotes shedding of the endometrium during menses
• B. It maintains the endometrium for pregnancy
• C. It stimulates ovulation
• D. It directly stimulates GnRH release

Answer: (B)

Progesterone’s primary role after ovulation is to convert the lining of the uterus into a secretory, nourishing environment and to keep that endometrium intact so it can support an implanted embryo. This hormone is produced by the corpus luteum and, if pregnancy occurs, is supported further by hCG to keep progesterone levels high until the placenta can take over. By promoting a secretory endometrium and reducing uterine contractions, progesterone helps maintain the pregnancy.

Shedding of the endometrium (menses) happens when progesterone withdrawal occurs, not when progesterone promotes shedding. Ovulation is triggered by an LH surge, not by progesterone. GnRH release is regulated by the hypothalamus and is negatively fed back by progesterone, which tends to suppress GnRH, rather than directly stimulating it.