Which hormone does the corpus luteum primarily produce after ovulation?

• A. Estrogen
• B. Testosterone
• C. LH
• D. Progesterone

Answer: (D)

After ovulation, the ruptured follicle becomes the corpus luteum, a hormone-secreting structure primarily driven by LH. Its main product is progesterone, which transforms the endometrium into a secretory, receptive state and keeps the uterine lining suitable for implantation. This luteal progesterone support is essential for maintaining pregnancy if fertilization occurs, with hCG from the early pregnancy placenta rescuing the corpus luteum to continue progesterone production. If there’s no pregnancy, the corpus luteum regresses and progesterone falls, leading to menses.

Estrogen is still produced during the luteal phase but not at the same dominant level as progesterone; LH is the stimulus, not a product of the corpus luteum; and testosterone is not the primary hormone produced by the corpus luteum after ovulation.