For many women in their mid-forties, changes to their menstrual cycle can be both puzzling and concerning. These shifts may signal the onset of perimenopause, the transition phase before menopause. Here's what you need to know to recognize the signs and when to consult a specialist.
What does perimenopause look like?
Perimenopause typically begins around age 47, marked by irregular periods. "The biggest change women will notice is they skip a cycle," says Nanette Santoro, a professor of obstetrics and gynecology at the University of Colorado Anschutz School of Medicine. On average, symptoms start four years before the final period, but this can vary from months to a decade.
During early perimenopause, periods may be early or late by at least a week, with lighter or heavier flow. About 40% of women experience hot flashes. As perimenopause progresses, periods become even less frequent, sometimes two months apart. Hot flashes peak, affecting around 80% of women. Other symptoms like depression, sleep disturbances, vaginal dryness, and vulvar burning or itching may appear.
These symptoms stem from declining estrogen levels. The ovaries produce less estrogen, leading to lighter periods, hot flashes, sleep problems, and reduced genital resilience and lubrication.
If your periods have stopped due to hysterectomy, chemotherapy, or hormonal IUD use, you may not notice these changes. A blood test can help in such cases.
How do I know if I'm in perimenopause?
If you're over 45 with typical symptoms—like hot flashes or cycle changes—a clinical diagnosis is usually sufficient. "I don't need a blood test to tell you that this is perimenopause," says Santoro.
Estrogen tests can be misleading because levels fluctuate wildly. A normal level might just catch an upswing, while a low level could be normal at certain times. Blood tests are helpful if symptoms are atypical or occur earlier than expected, or to rule out thyroid problems or diabetes, which can cause similar symptoms.
For confusing cases—such as with an IUD—a test for anti-Mullerian hormone (AMH) can estimate remaining egg count, but it's not useful for all ages. At-home hormone test kits are not reliable predictors.
I think I'm in perimenopause—do I need to do anything?
If you have core menopause symptoms, see a specialist. Hormonal and non-hormonal therapies are available but underprescribed. An OB-GYN or primary care clinician with menopause training can help.
Lifestyle basics become crucial: good sleep, quitting smoking, regular exercise, and a high-fiber diet. Also, monitor for midlife conditions like high cholesterol, high blood pressure, and diabetes, especially if there's a family history.
Keren Landman MD is an independent health reporter and infectious disease physician.