Glossary term

Perimenopause

Also known as Menopausal transition - Climacteric

The 4-10 year hormonal transition before menopause. Usually starts mid-40s with irregular cycles and sleep shifts.

Perimenopause is the transitional window before your final menstrual period, typically lasting 4-10 years and starting in the mid-40s (though it can begin in the late 30s). Estradiol becomes erratic rather than steadily declining - which is why symptoms feel chaotic. Earliest signs: shorter cycles, luteal-phase progesterone drop, disrupted sleep, and mood volatility. FSH above 25 mIU/mL on two random draws is the standard staging marker. HRT started during perimenopause tends to work better than waiting until post-menopausal symptoms set in. Start with the Women's Hormone panel to confirm where you are.

Medically reviewed byDr. Lena Okafor, MD

Medical Director - updated April 2026 - How we review