Perimenopause

When does menopause start?

The final period usually occurs between the ages of 45 and 55, and it can happen earlier. Perimenopause is the time before that, when periods change and symptoms can start.

By Ines Kovac. Published 23 October 2026. 5 minute read.

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Perimenopause, menopause and postmenopause

Perimenopause is when your periods become irregular, and menopause is when they stop altogether. Menopause means 12 months with no period when you are not using hormonal contraception (NHS: menopause and perimenopause). Perimenopause ends at that point. Postmenopause is the time after it.

A fall in hormone levels is what causes menopause, and it can affect anyone who has periods. The usual ages above come from that same NHS page. The NHS fertility page gives 51 as the average age for menopause in the UK.

What age does perimenopause start?

There is no single age at which perimenopause starts. It begins when the cycle changes and symptoms begin. Menopausal symptoms can begin months or even years before periods stop (nidirect: menopause).

The Canadian Menopause Society, in its summary of the STRAW staging used in international guidance, says perimenopause can last about 4 to 8 years before menopause, and in some people 10 years or longer. That span is the length of the stage. How long menopause lasts is the separate question of how long the symptoms themselves go on.

NICE says people from some ethnic minority backgrounds, and people with some lifelong conditions, may reach menopause at a younger age.

Early menopause means regular periods have stopped before 45. Premature menopause means periods have stopped before 40 (NHS: early or premature menopause). The labels and the tests used at those ages are in the early menopause guide.

The first signs of perimenopause

One of the first signs of perimenopause is usually a change to your periods. They may happen more often or less often, and bleeding may get heavier or lighter (NHS: menopause symptoms).

The National Institute on Aging describes the transition as usually starting with a change in cycle pattern, often with hot flashes or other symptoms alongside.

Menopause symptoms can occur before the cycle changes, and menstrual cycle changes can occur without menopause symptoms. The Canadian Menopause Society notes both patterns.

The Menopause Society describes how cycles tend to change. As perimenopause progresses, cycle length may vary by 7 days or more from your usual pattern. Near the beginning, a skipped period may only be occasional. In the late menopause transition, women may go 60 days or more without a period. The perimenopause or menopause stage checker sets your age and the date of your last period against that kind of gap.

Early signs of perimenopause

A hot flush is when the face, neck and chest suddenly feel very hot or very cold. It can make you sweat a lot, and it can cause palpitations, anxiety or dizziness. Flushes can happen in the daytime. At night, the same episode is a night sweat. When a racing heart is the part that worries you, the heart palpitations guide sets out when to talk to a GP.

Hot flashes and night sweats are the most commonly reported symptoms of the menopause transition. The Menopause Society uses those names for the daytime episodes and the night-time ones just described.

Sleep and mood can shift in the same years. The menopause symptom checklist for your GP is the wider list to print, with the period changes and the flushes on it. When flushes are the symptom you want to track, a hot flush diary logs episodes and triggers for that visit.

How doctors identify perimenopause from age 45

From age 45, NICE says perimenopause can be identified without laboratory tests in otherwise healthy women, trans men and non-binary people registered female at birth. The pattern is vasomotor symptoms that have recently started, together with any change in the cycle. Vasomotor symptoms are those flushes and sweats.

The NHS says there is no routine test for perimenopause or menopause. A doctor may diagnose it from your age and your symptoms.

From 45, measuring follicle-stimulating hormone does not help with the diagnosis, because levels fluctuate during perimenopause and the result would not change management (NICE quality statement 143). The early menopause guide covers testing before 45.

When to book a GP appointment

Talk to a GP if menopausal symptoms are troubling you, including if they start before 45. nidirect gives that advice.

See a GP if you still have periods and the bleeding has become heavier than it was. The NHS symptoms page includes that warning.

Print the checklist and take it in. If you want to see which stage your age and last period point to before the visit, use the stage checker. HRT for menopause covers what the treatment is for, and the timing while periods continue or after they have stopped.

What to read next

The perimenopause topic hub links to the other guides on this stage. The duration guide covers how long symptoms continue, from the first changes through the years after menopause. That question is separate from how long the perimenopause stage can run.

My take

I would start by noting the month your periods changed in frequency or flow, and whether flushes had already begun, because either can happen first. From 45, that pair is what NICE uses to identify perimenopause without a hormone test, and it is what I would take to a GP. If symptoms are troubling, bleeding is heavier, or the changes began before 45, I would book the GP visit with the printed list.