Does follicle loss during the menopausal transition cause rising FSH and skipped ovulation?

The hormonal changes during the menopausal transition are driven by a well-documented feedback loop between the ovaries and the brain. As the number of available ovarian follicles declines, the production of regulatory hormones shifts, leading to the clinical symptoms of perimenopause.

Clinical and effectiveness evidence

The transition to menopause is characterized by distinct stages of hormonal and menstrual change, as defined by the STRAW+10 (Stages of Reproductive Aging Workshop) criteria.

• Hormonal shifts: Research from the Study of Women's Health Across the Nation (SWAN) confirms that a rise in follicle-stimulating hormone (FSH) is a hallmark of the transition. In the late perimenopausal stage, FSH levels typically rise above 25–30 IU/L.
• Cycle variability: This elevated FSH is strongly correlated with menstrual irregularity. Specifically, women in late perimenopause often experience "skipped" cycles, defined as 60 days or more of amenorrhea, which is a direct result of failed follicular maturation and ovulation.
• Predictive markers: While age is a factor, reproductive hormones—specifically high FSH and low inhibin B—are more accurate predictors of anovulatory cycles (cycles where no egg is released) than chronological age alone.

Mechanistic explanations

The disruption of the hypothalamic-pituitary-gonadal (HPG) axis explains the progression toward menopause through the loss of negative feedback:

• Follicle depletion: Inhibin B is produced by the granulosa cells of small, early-stage follicles. As the primordial follicle pool reaches a critical low, the total output of inhibin B drops. This is often the earliest detectable marker of reproductive aging.
• Loss of feedback "brakes": Under normal conditions, inhibin B and estradiol (E2) act as "brakes" on the pituitary gland, suppressing FSH secretion. Inhibin B specifically antagonizes activin signaling in the pituitary to limit FSH synthesis.
• Compensatory FSH rise: As follicle numbers fall and inhibin B/estradiol levels decline, the pituitary gland loses this negative feedback. In an attempt to stimulate the remaining follicles, the pituitary increases FSH production.
• Ovulatory failure: Although FSH rises to compensate, the remaining follicles are often less sensitive to its signals or are metabolically impaired (showing reduced mitochondrial ATP and increased apoptosis). This results in shortened follicular phases, "luteal out of phase" (LOOP) events, or a total failure to recruit a dominant follicle, leading to skipped ovulation.

Bottom line

The claim is fully supported by reproductive endocrinology. The depletion of ovarian follicles reduces the inhibitory signals (inhibin B and estradiol) sent to the brain, causing a compensatory rise in FSH that ultimately destabilizes the menstrual cycle and leads to irregular or skipped ovulation.