Does ovarian follicular depletion lower estradiol and inhibin feedback, raising FSH and LH while progesterone stays low?

Ovarian aging and the menopausal transition are characterized by progressive follicular depletion, increasingly irregular ovulation, and altered hypothalamic-pituitary-ovarian feedback. The claim is largely physiologically correct, but the pathways to FSH versus LH elevation need to be distinguished.

Hormonal feedback and gonadotropins

• Depletion of growing granulosa-cell-containing follicles reduces inhibin B, with inhibin A also declining as follicular function is lost. Because inhibin selectively restrains pituitary FSH, its loss is a direct driver of rising FSH and may precede a sustained estradiol decline.
• Declining ovarian estradiol reduces negative feedback at hypothalamic and pituitary levels. This contributes to increased FSH and provides the well-supported feedback explanation for increased LH, particularly later in the transition and after menopause.
• The important qualification is that reduced inhibin feedback should not be considered a direct cause of elevated LH; its principal effect is FSH-selective. Estradiol can fluctuate or remain temporarily preserved early in perimenopause, while FSH may already be elevated.

Ovulation and progesterone

• Follicular depletion leads to increasingly irregular and ultimately absent ovulation. Without ovulation, there is no post-ovulatory corpus luteum and therefore no normal luteal progesterone rise.
• Longitudinal SWAN findings support this trajectory: luteal-activity cycles decline and low-pregnanediol, non-luteal cycles become more frequent approaching the final menstrual period, especially during the final three years.

Clinical interpretation

• During perimenopause, FSH, LH, estradiol, and progesterone vary substantially cycle to cycle. In women aged 45 or older, menopausal status is generally determined clinically from menstrual history and symptoms rather than isolated hormone values; hormonal therapy or contraception further complicates interpretation.

Bottom line

• Follicular depletion lowers inhibin and estradiol feedback; both contribute to higher FSH, while estradiol-feedback loss—not inhibin loss—supports higher LH. Loss of ovulation directly produces low progesterone by eliminating corpus-luteum production.