What is the role of progesterone during the menstrual cycle?

• A. Prepares endometrium for implantation, myometrial contractions
• B. Stimulates ovulation
• C. Causes follicle maturation
• D. Induces lactation

Answer: (A)

Progesterone after ovulation shifts the endometrium from a proliferative to a secretory state, with glands becoming more developed and vascular, creating a nourishing environment ready for possible embryo implantation. It also helps keep the uterine lining intact by relaxing the myometrium, reducing contractions so the endometrium isn’t shed and a potential embryo can implant. If pregnancy doesn’t occur, progesterone levels fall and the secretory lining breaks down, leading to menstruation. These actions—preparing the endometrium for implantation and modulating uterine activity—best capture progesterone’s role in the cycle, while other choices involve different hormones.