A 26-year-old female patient has FSH: 18 IU/L (elevated), LH: 22 IU/L (elevated), AMH: 0.1 ng/mL (very low), and antral follicle count of 2. These findings are consistent with premature ovarian insufficiency (POI). What is the primary pathophysiological mechanism of the elevated gonadotropins in this condition?

• A Autoantibodies against FSH receptors block FSH action, causing compensatory FSH hypersecretion
• B GnRH pulse frequency increases due to reduced hypothalamic estrogen receptor expression
• C Elevated prolactin from associated autoimmunity reduces dopaminergic inhibition of FSH
• D Loss of follicular granulosa cells eliminates inhibin B and estradiol, removing negative feedback on pituitary FSH and LH secretion ✓

Explanation

In premature ovarian insufficiency (POI), depletion of the follicular pool means absence of granulosa cells, which normally produce inhibin B (FSH-specific inhibitor) and estradiol (LH and FSH inhibitor via negative feedback). With loss of these feedback signals, the hypothalamo-pituitary axis is unrestrained, and both FSH (primarily inhibin-sensitive) and LH (primarily estradiol-sensitive) rise markedly. Low AMH reflects absent granulosa cell mass. The hypergonadotropic pattern (high FSH/LH + low estrogen) distinguishes primary ovarian failure from hypogonadotropic hypogonadism (low FSH/LH).

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.