At what point in the menstrual cycle do gonadotropin levels peak?

At what point in the menstrual cycle do gonadotropin levels peak?

• A. During the follicular phase
• B. During the luteal phase
• C. Midpoint of the cycle
• D. Several days prior to ovulation

Answer: (C)

Gonadotropins (LH and FSH) rise under GnRH control from the pituitary, and their peak happens around ovulation. As estrogen from the maturing follicle rises, it triggers a brief positive feedback that causes a surge in LH (with a smaller rise in FSH) right at the midpoint of the cycle. That LH surge drives ovulation, so the highest gonadotropin levels occur at the cycle’s midpoint. After ovulation, progesterone from the corpus luteum provides negative feedback, lowering gonadotropin levels in the luteal phase. Hence, the midpoint of the cycle best reflects the peak.

Gonadotropins (LH and FSH) rise under GnRH control from the pituitary, and their peak happens around ovulation. As estrogen from the maturing follicle rises, it triggers a brief positive feedback that causes a surge in LH (with a smaller rise in FSH) right at the midpoint of the cycle. That LH surge drives ovulation, so the highest gonadotropin levels occur at the cycle’s midpoint. After ovulation, progesterone from the corpus luteum provides negative feedback, lowering gonadotropin levels in the luteal phase. Hence, the midpoint of the cycle best reflects the peak.