When does perimenopause start? Age and first signs
Perimenopause usually starts in a woman's mid-to-late 40s, and most women begin the transition between 45 and 55. [1][2] There is no test that marks the first day; what usually marks it is a change in your periods. [1]
What age does perimenopause start?
Three US authorities, three overlapping answers. The Office on Women's Health: perimenopause usually starts in a woman's mid-to-late 40s. [1] The National Institute on Aging: most women begin the menopausal transition between ages 45 and 55. [2] ACOG: beginning in your 30s and 40s the amount of estrogen produced by the ovaries begins to fluctuate, and the phase itself usually begins in the mid-40s and may last from ages 45 to 55, although the timing varies from person to person. [3][4] Put together: hormonal change can be under way in the late 30s, noticeable change most often arrives around 45 to 47, and the whole transition typically ends with menopause at an average age of 51 to 52. [1][3]
What is the first sign it has started?
Your periods. The Office on Women's Health says irregular periods may be your first sign, and the Menopause Society describes the earliest changes as subtle: cycles commonly become a little shorter than usual, the number of bleeding days may be fewer or greater, and flow may be heavier or lighter. [1][5] Hot flashes, trouble sleeping and mood changes can arrive alongside, but for many women the calendar changes first. [1] Our article on the signs of perimenopause lists them all with sources.
Can perimenopause start at 40, or in your 30s?
It can begin earlier than the mid-40s for some women. [1] The line that matters medically is 40: the Office on Women's Health says a provider may test hormone levels if your periods stop at an early age, before 40, and that this is one of the few situations where the test is useful. [1] UK guidance draws the same lines: NICE says to consider an FSH blood test to help confirm menopause only in women aged 40 to 45 with menopause-associated symptoms including a change in cycle, and in women under 40 in whom menopause is suspected; at 45 and over it says not to use laboratory tests at all. [6] So if you are 38 and your periods have changed, that is a reason for an appointment and possibly a test, not a reason to assume.
What makes it start earlier or later?
Smoking: studies show it can bring menopause on up to two years earlier than in women who don't smoke. [1] Family: the age your mother went through menopause is one clue to when you might. [1] Pregnancy, especially more than one, may delay it. [1] Surgery: if both ovaries are removed, periods stop and menopause symptoms can begin immediately, and the Menopause Society notes that hot flashes after surgical menopause tend to be more frequent and severe. [2][7] Chemotherapy can also bring menopause earlier. [1] And race and ethnicity: the National Institute on Aging says Black women are more likely than white women to have an early onset, more symptoms and symptoms for longer, while Asian women are less likely to suffer from menopausal symptoms; NICE likewise says people from some ethnic minority backgrounds may experience menopause at a younger age. [2][6]
Is there a test to tell if it has started?
Not a reliable one, which surprises most women. The Office on Women's Health says that for most women hormone levels go up and down unpredictably during the transition, so it is difficult to tell for sure from a blood test whether you have gone through menopause or are getting close, and providers don't usually recommend the test without a medical reason. [1] The National Institute on Aging says your doctor may instead ask about your age, symptoms and family history. [2] NICE puts it most directly: identify perimenopause without laboratory tests in otherwise healthy women aged 45 or over who have recently started hot flashes and have changes in their menstrual cycle. [6] A "normal" hormone result at 46 does not mean you are not in perimenopause.
What to track from your early 40s
The first day of each period and roughly how heavy it was, on a calendar or an app, so a pattern can be reviewed later; the Menopause Society suggests this because in the years before perimenopause most women have a fairly consistent pattern, which makes changes noticeable. [5] The age your mother and sisters reached menopause. [1] And the month hot flashes or night sweats first appear, if they do. [7]
When to talk to your clinician
If your periods have changed before 40, go; that is the case where testing is appropriate. [1] At any age, ACOG says it is not normal to have bleeding or spotting between periods, bleeding or spotting after sex, bleeding heavier or lasting more days than usual, or any bleeding after menopause, and those belong in an appointment whatever stage you think you are at. [4] And if you are not sure whether what you are feeling is the start of perimenopause or something else, that uncertainty is itself a good reason to ask. [2]
Sources
- Office on Women's Health, Menopause basics. Page last updated April 2, 2026. Retrieved 2026-10-17.
- National Institute on Aging, What Is Menopause? Content reviewed October 16, 2024. Retrieved 2026-10-17.
- American College of Obstetricians and Gynecologists, The Menopause Years. Last reviewed December 2025. Retrieved 2026-10-17.
- American College of Obstetricians and Gynecologists, Perimenopausal Bleeding and Bleeding After Menopause. Last reviewed February 2024. Retrieved 2026-10-17.
- The Menopause Society, Perimenopause (patient education). Retrieved 2026-10-17.
- NICE (UK), Menopause: identification and management, NG23, recommendations 1.3.1, 1.3.3, 1.3.4 and 1.3.6. Last updated April 15, 2026. Retrieved 2026-10-17. UK guidance.
- The Menopause Society, Hot flashes (patient education). Retrieved 2026-10-18.
Every statement above was checked against the linked source on the date shown. This article is education, not individual medical advice. Related: How long does perimenopause last? · What is perimenopause?