Perimenopause
Perimenopause is the transition period -- typically 4 -- 8 years before the final menstrual period -- during which ovarian function becomes irregular and estrogen fluctuates widely before declining. Many women experience significant symptoms during this phase yet receive little clinical attention because they are still menstruating.
Symptoms
Irregular cycle length and flow, hot flashes, night sweats, sleep disruption, mood lability, irritability, anxiety, brain fog, breast tenderness, and decreased libido. Symptoms may begin a decade before actual menopause and often wax and wane with fluctuating estrogen levels.
Causes and risk
The hypothalamic-pituitary-ovarian axis becomes progressively dysregulated as the number of functional follicles declines with age. Irregular ovulation leads to progesterone deficiency (luteal phase shortening) before estrogen levels significantly fall. Stress, poor sleep, and thyroid dysfunction can amplify symptoms.
How it is evaluated
FSH and estradiol levels are highly variable in perimenopause and single measurements are often unreliable. Clinical history is the primary diagnostic tool. We check TSH, iron studies, and complete blood count to rule out contributory conditions. Anti-Müllerian hormone (AMH) can help estimate remaining ovarian reserve.
Treatment
Low-dose oral contraceptives or progesterone therapy can stabilize cycle irregularity and reduce symptoms in eligible women. For women who prefer to avoid hormones, SSNRIs and cognitive behavioral therapy for insomnia have evidence. We discuss bone health, cardiovascular monitoring, and contraception (fertility is reduced but not absent in perimenopause).