What's the difference: perimenopause vs menopause?

The simplest way to remember it: perimenopause is the years-long transition leading up to menopause, and menopause is a single point in time — the day you've gone 12 months without a period.

Perimenopause (“around menopause”) is the run-up, often starting in your forties (sometimes late thirties) and lasting anywhere from a couple of years to a decade. Your hormones — especially oestrogen and progesterone — fluctuate erratically, which is why this stage causes most of the well-known symptoms: irregular periods, hot flushes, broken sleep, mood swings, and brain fog. Crucially, you're still having periods and can still get pregnant.

Menopause itself is technically just one day — marked once you've had no period for 12 straight months (average age around 51). Everything after that is post-menopause, when hormone levels settle at a new, lower baseline. Confusingly, most people say “menopause” loosely to mean the whole experience, but medically the distinction matters: the unpredictable, symptom-heavy phase is usually perimenopause, not menopause.

What to do: if you're in your forties with changing periods and new symptoms, you're most likely in perimenopause — and you don't have to wait until periods stop to get help. Treatments and lifestyle changes work during the transition, not just after it. Tracking your cycle and symptoms gives you and your doctor a much clearer picture of where you are.