Perimenopause

Contents

1. A definition built on stages
2. When it begins
3. How long it lasts
4. Hormones in flux
5. Changes in the cycle
6. The range of symptoms
7. What a national survey found
8. Why it is hard to confirm
9. The historical echo

Perimenopause, among the menopause related concerns in the gynecologic care Candace Cooley has provided since completing residency in 1998, has been described more cautiously since 2005, the year the National Institutes of Health weighed which symptoms truly belong to menopause. A 2024 commentary in PubMed Central recalls that the institutes found hot flashes with night sweats and vaginal dryness to be the two clearly attributable ones, and it adds a second conclusion from the same period: women’s experiences vary so much that there may be no universal menopause syndrome at all.¹ Perimenopause is the stretch of years in which that variation plays out.

A definition built on stages

Researchers define the transition by the menstrual cycle. The commentary explains that the STRAW +10 classification stages reproductive aging by cycle changes and by follicle stimulating hormone, a pituitary hormone whose steadily high levels can confirm menopause but which may sit in the normal range during perimenopause.¹ A 2025 survey paper in npj Women’s Health sets out the stages: an early phase of occasional missed cycles or lengths that vary by seven days or more, a late phase with gaps of 60 days to a year, and menopause itself, the final period. In this scheme perimenopause covers the years before the final period and the twelve months after it.²

Figure

The stages of the transition

1. 01
   Early stageOccasional missed cycles, or cycle lengths that vary by seven days or more
2. 02
   Late stageGreater irregularity, with stretches of 60 days to a year without a period
3. 03
   Final periodMenopause is the final menstrual period, known only once 12 months have passed
4. 04
   First year afterPerimenopause ends 12 months after the final period, overlapping the start of postmenopause

When it begins

The starting point varies widely. The American College of Obstetricians and Gynecologists notes that estrogen from the ovaries begins to fluctuate in the 30s and 40s and puts the average age of menopause at 51.³ Columbia University Irving Medical Center gives 47 as the average age at which perimenopause starts in the United States, and an obstetrician there describes it as something seen only in the rearview mirror.⁴ NPR reported in 2020 that the transition can begin as much as a decade before menopause and that about 1 percent of women in the United States reach menopause at 40 or younger.⁵

How long it lasts

Estimates of length differ by source. Columbia gives four to ten years,⁴ the survey paper five to ten,² and Healthline, interviewing the medical director of The Menopause Society, four to eight, with an estimated 2 million women in the United States entering perimenopause each year.⁶ The National Institute on Aging says menopause symptoms last between two and eight years, varying with genetics, ethnicity, culture and smoking.⁷

Figure

Perimenopause and menopause

	Perimenopause	Menopause
What it is	The menopausal transition, the years before menopause	The point when periods stop permanently
How it is known	Usually by changes in menstrual cycle patterns, often with hot flashes	Confirmed after a full year with no period or spotting
Timing	Most women begin between 45 and 55	Average age 52 in the United States

The institute also describes differences between groups: compared with White women, Black women tend to reach menopause earlier, have more symptoms and have them for longer, while Asian women are less likely to have troublesome symptoms. Smoking is linked to an earlier menopause and more severe symptoms, and surgery that removes both ovaries brings symptoms on at once.⁷

Hormones in flux

Perimenopause is often pictured as a steady loss of estrogen, but the associate medical director of The Menopause Society told NPR in 2025 that the defining feature is fluctuation, which is why the experience can be so uneven, and that many women feel better once they are through it.⁸ Columbia’s obstetrician compares it to puberty, with an uneven decline rather than a smooth one as the ovaries wind down.⁴ The institute adds that production of estrogen and progesterone falls greatly over the transition.⁷

Changes in the cycle

The cycle is usually the first sign. A psychiatrist quoted by NPR in 2020 calls the menstrual pattern the feature that really defines the lead up to menopause, with shorter cycles, longer ones, skipped ones and changes in flow.⁵ The college describes cycles that lengthen or shorten and flow that lightens or grows heavier, and notes that bleeding changes should still be reported.³ Prolonged bleeding is very common: the commentary cites data showing it affects more than 90 percent of women at least once during the transition and nearly 80 percent at least three times.¹ The institute lists the patterns that call for a medical look: periods very close together, heavy bleeding, bleeding after sex or between periods, periods lasting more than a week, and any bleeding after a year without periods.⁷

Figure

Prolonged bleeding in the transition

of women with prolonged menstrual bleeding at least once

Over 90%

of women with prolonged bleeding on at least three occasions

Nearly 80%

The range of symptoms

Beyond the cycle, the college lists hot flashes, sleep problems and changes in the vagina and urinary tract.³ The medical director interviewed by Healthline names irritability and anxiety as the most common mood symptoms and notes that women with past premenstrual or postpartum mood problems are at higher risk; she cautions against filing every midlife complaint under perimenopause, since palpitations or itching can signal other disease.⁶ The survey paper cites research finding that women in perimenopause are two to four times more likely to have an episode of major depression.² Rates of hot flashes alone range from 3 to 86 percent across studies worldwide, and the commentary notes that women who enter the transition expecting the worst are more likely to report troublesome symptoms.¹ Healthline cites a 2025 study in which nearly 5,000 people logged about 145,000 symptoms across the stages of menopause, roughly 39 percent of them in perimenopause.⁶ Body shape changes too. Columbia reports no evidence that perimenopause itself causes weight gain, but notes a shift of weight toward the belly, hips and thighs,⁴ and a gynecologist quoted by NPR points to research showing jumps in aging around 45 and 60 in both sexes, so not every change in metabolism is hormonal.⁸ Hot flashes have their own entry, vasomotor symptoms, and so does the heart in the menopause years.

What a national survey found

The 2025 survey of 4,432 women aged 30 and older found that 20.7 percent had consulted a medical professional about perimenopause or menopause, that 70.8 percent of those were told they were in perimenopause, and that 55.4 percent of women aged 30 to 35 reported moderate or severe symptoms on a standard rating scale.² Skipped periods, hot flashes, vaginal dryness and frequent urination were among the features most closely linked to a clinical diagnosis.²

Figure

A survey of perimenopause in the United States

had consulted a medical professional about perimenopause or menopause

20.7%

of those consulting were told they were in perimenopause

70.8%

of women aged 30 to 35 reported moderate or severe symptoms

55.4%

Why it is hard to confirm

No single test settles it. The psychiatrist quoted by NPR in 2020 explains that hormone levels are too erratic for one blood test to be definitive,⁵ and a gynecologist quoted in 2025 describes first checking for conditions that can mimic it, among them thyroid disease, early diabetes and depression.⁸ The institute notes that a blood test may be suggested in some cases, such as periods that stop at an early age.⁷ Columbia likewise calls confirmation unnecessary in most cases, since fluctuating hormones make current tests unreliable, but advises a medical review when perimenopause appears to begin before 40.⁴ Women themselves are often unsure: the Menopause Society director reports a study in which women’s own sense of their stage matched an expert’s only about half the time.⁶

The historical echo

Columbia notes that earlier generations of women called this transition the change, if they mentioned it at all.⁴ The same reticence returns in modern form: the Menopause Society director observes that girls are told what to expect before their first period, but there is no equivalent conversation for the other end.⁶ Treatment choices, including menopause hormone therapy, have their own history, and whether any of them suits one woman is for her and her own clinician to weigh together. The 2005 caution about which symptoms truly belong to menopause still applies.