What is the role of progesterone in the menstrual cycle?

• A. It stimulates the growth of the endometrium
• B. It triggers ovulation
• C. It is the major female sex hormone and is often referred to as the 'pregnancy hormone'
• D. It stimulates the production of estrogen

Answer: (C)

Progesterone's main job in the menstrual cycle is to prepare and maintain the uterine lining for a possible pregnancy and to support early pregnancy. After ovulation, the corpus luteum produces progesterone, signaling the endometrium to become secretory and rich in nutrients that could nourish an embryo. It also helps calm uterine contractions and supports the development of breast tissue in case pregnancy occurs. Because its levels stay elevated during pregnancy to sustain the uterine environment, progesterone is often called the pregnancy hormone. This role is distinct from the hormone that triggers ovulation—luteinizing hormone—and from estrogen, which primarily drives the growth and thickening of the endometrium earlier in the cycle.