Perimenopause: what is actually happening to you

The short version

Perimenopause means "around menopause". Your ovaries produce less oestrogen, but not in a straight line down. Levels swing, sometimes higher than they ever were, sometimes very low, often within the same month. Those swings are what cause symptoms.

Menopause itself is a single day: the point twelve months after your last period. Everything before it is perimenopause. Everything after is postmenopause.

What is actually happening

Through your reproductive years, oestrogen and progesterone rise and fall in a rhythm your body knows. In perimenopause that rhythm breaks down. Ovulation becomes irregular, so progesterone drops away first and often quite sharply. Oestrogen becomes erratic rather than simply low.

This matters because oestrogen receptors sit in almost every system you own: the brain, the bones, the skin, the bladder, the joints, the blood vessels that control your body temperature. When the supply becomes unpredictable, so do you. That is why the symptoms feel unrelated to each other and why they come and go rather than arriving steadily.

When it starts

Most women begin perimenopause in their mid-forties. It commonly lasts four to eight years, and the average age of menopause in the UK is around 51.

But the range is wide, and "average" is doing a lot of work in that sentence. Perimenopause can start in the late thirties. It can be shorter than a year or longer than a decade. Starting earlier than most does not mean something is wrong, though menopause before 40 is called premature ovarian insufficiency and does need proper assessment.

What it feels like

The NHS lists changes to periods as the first sign for most women: closer together or further apart, heavier or lighter, sometimes both in the same year.

Alongside that, the symptoms women actually report:

• Waking at three in the morning, mind racing, unable to drop back off
• Hot flushes and night sweats
• Brain fog, losing the thread of a sentence, the word arriving late
• Anxiety that was not there before, or a temper you do not recognise as yours
• Joint aches and stiffness that arrived with everything else
• Dryness, discomfort during sex, or repeated urinary infections
• Exhaustion that sleep does not fix

The NHS notes that symptoms usually last seven to nine years and can change over that time. That is not a sentence anyone says out loud often enough. This is not a bad few months.

How it is diagnosed

For most women over 45, UK guidance is that perimenopause is diagnosed on symptoms and cycle pattern alone. No blood test is required, because hormone levels swing so much from day to day that a single reading tells you very little.

Under 45, and particularly under 40, testing has more of a role, and a clinician will say so.

This surprises people, because a blood test feels like proof. What actually establishes the picture is a careful history: what your cycle is doing, which symptoms you have, how long they have been there, and what else could explain them.

What helps

Treatment is not automatic and it is not for everyone, but for most healthy women with symptoms, replacing the oestrogen your ovaries are no longer reliably making is the first-line option in UK guidance. Where you still have a womb, progesterone is included to protect the womb lining.

Lifestyle changes help around the edges and are worth doing. They do not replace the hormone that has gone.

The honest position is that this is an individual decision, made properly, with your history in front of a clinician. That is what an assessment is for.

What to do next

If you recognise yourself in this, the useful next step is to get the pattern written down rather than carrying it around: which symptoms, how severe, how long, and what your cycle is doing. That is what a clinician needs to see, and it is what our free assessment collects.

If your periods have already stopped for twelve months, you are past perimenopause and postmenopausal, and the treatment picture is slightly different.

And one thing that is not perimenopause: any bleeding after your periods have stopped for a year needs checking by a doctor, usually within weeks.