Perimenopause

By RRM Academy Reviewed by Dr. Naomi Whittaker, MD, Board-Certified OBGYN, MIGS, NFPMC, FCI Updated May 14, 2026

Perimenopause is the biological transition period preceding menopause, typically spanning 4 to 10 years, during which ovarian function declines progressively and menstrual cycle patterns become irregular. The staging criteria established by the Stages of Reproductive Aging Workshop (STRAW+10) define early perimenopause by variable cycle length and late perimenopause by cycles 60 or more days apart, concluding at the final menstrual period.¹ This transition follows biology, not a specific calendar age, though it most commonly begins in the mid-forties.

Hormonally, perimenopause brings volatility rather than simple decline. FSH rises irregularly, AMH falls progressively as the ovarian follicle pool depletes, estradiol fluctuates widely between cycles, and anovulatory cycles become more frequent.² This hormonal instability produces the vasomotor symptoms, sleep disruption, and mood changes commonly associated with the menopausal transition.

Fertility does not end at the onset of perimenopause. Ovulation still occurs, and conception remains possible, though the probability of successful pregnancy declines as anovulatory cycles increase and egg quality diminishes with advancing follicle depletion. Couples who do not wish to conceive should understand that contraceptive needs persist until 12 consecutive months of amenorrhea confirm Menopause. For couples pursuing pregnancy during perimenopause, the clinical evaluation differs from care in younger women, with particular attention to ovarian reserve, cycle quality, and the frequency of ovulatory cycles.

This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.