Perimenopause is the transition, often lasting several years, when hormones fluctuate and periods change. Menopause is one point in time: 12 months without a period. Here is how to tell where you are.
The short answer
Perimenopause is the lead-up to menopause, usually starting in the 40s, when estrogen rises and falls unpredictably and periods change. It lasts on average about 4 years but can be longer. Menopause is reached after 12 months in a row without a period, at an average age of about 51. Everything after that is postmenopause. Symptoms are often strongest in late perimenopause.
Side by side
| Perimenopause | Menopause / postmenopause | |
|---|---|---|
| What it is | The transition, with fluctuating hormones | 12 months without a period, and the years after |
| Typical age | Early to mid 40s onward | About 51 on average (45–55 typical) |
| Periods | Irregular, heavier or lighter, skipped | Stopped |
| Pregnancy possible? | Yes, contraception still needed | No, after 12 months (24 months if under 50) |
| Common symptoms | Cycle changes, hot flushes, poor sleep, mood changes, brain fog | Hot flushes may continue; vaginal dryness and bone loss become more important |
| Diagnosis | Mainly age and symptoms; blood tests often unhelpful | 12 months without a period |
The short version
How to tell where you are
If you are over 45 with changing periods and symptoms such as hot flushes or poor sleep, you are probably in perimenopause, and blood tests are usually not needed because hormone levels swing day to day. If you are under 45, or using hormonal contraception that hides your periods, see a doctor to work it out.
Treatment
Treatment is based on symptoms, not on which stage you are in. Hormone therapy, non-hormonal medicines, vaginal estrogen, CBT and lifestyle changes can all help, during perimenopause as well as after menopause.
Frequently asked questions
How do I know if I am in perimenopause or menopause?
If you still have periods, even irregular ones, you are in perimenopause. Menopause is confirmed after 12 months without a period.
How long does perimenopause last?
About 4 years on average, though it can be shorter or last up to 10 years.
Can you get pregnant in perimenopause?
Yes. Use contraception until 12 months after your last period if over 50, or 24 months if under 50.
Are symptoms worse in perimenopause or menopause?
Many symptoms peak in late perimenopause and the first year or two after the final period.
Track the transition
The free Menopause Starter Kit includes a symptom checklist to help you and your doctor see where you are.
