Perimenopause

The years before menopause when hormone levels change and you start to get symptoms, while still having periods.

What does perimenopause mean?

Perimenopause: The years before menopause when hormone levels change and you start to get symptoms, while still having periods.

How it is used in the Splash library

Perimenopause, usually between 45 and 55
From “Missing periods (amenorrhoea)”
So you can still get pregnant during perimenopause.
From “Contraception in your 40s and 50s”
In the app study, average cycle length got a little shorter with age in adulthood, then changes again in perimenopause.
From “What is a normal cycle length?”
The start of perimenopause (usually between 45 and 55).
From “Late period? The common reasons”
The NHS says menopause and perimenopause usually affect people between 45 and 55, and the UK average age of menopause is 51.
From “Your cycle through life”

Perimenopause explained

Perimenopause is the time before menopause when your hormone levels start to change and your periods become less predictable. It ends 12 months after your last period, when you have reached menopause.

During perimenopause, oestrogen and progesterone rise and fall unevenly rather than gradually declining. That can make cycles shorter or longer, periods heavier or lighter, and symptoms come and go.

What's typical

It usually starts in your mid-40s and can last several years, though some people notice changes in their late 30s.

Early signs often include cycles that change length, heavier periods, worse PMS, trouble sleeping, night sweats, mood changes, anxiety and brain fog. Hot flushes often come later.

You can still get pregnant during perimenopause, so contraception is advised until 2 years after your last period if you are under 50, or 1 year if you are over 50 (NHS).

When to talk to a GP, nurse or pharmacist

Symptoms are affecting your daily life. A GP can usually diagnose perimenopause from your symptoms alone if you are over 45 (NICE NG23).
You have very heavy periods, bleeding between periods or after sex, or periods much closer together than usual.
You are under 45 and your periods have changed or stopped.

In the UK you can call NHS 111 for advice at any time. In an emergency call 999 (UK) or 911 (US). This is general information, not medical advice.

Where it comes up

ConditionsMissing periods (amenorrhoea)4 min read ContraceptionContraception in your 40s and 50s5 min read Cycle basicsWhat is a normal cycle length?4 min read Cycle basicsLate period? The common reasons4 min read Cycle basicsYour cycle through life4 min read · Deep dive PerimenopauseWhat is perimenopause?4 min read PerimenopausePerimenopause symptoms: the full list4 min read PerimenopauseHow your cycle changes in perimenopause4 min read · Deep dive PerimenopauseHRT: a balanced look6 min read · Deep dive PerimenopauseSleep and mood in perimenopause4 min read PerimenopauseTalking to a doctor about perimenopause4 min read Cycle basicsPeriod twice in one month: is it normal?4 min read Period carePeriod lasting longer than 7 days: what to know4 min read Apps & privacyHow accurate are period tracker apps?6 min read · Deep dive

Sources

Sources checked October 2026.

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