Irregular periods are often the first sign of perimenopause. Cycles can get shorter, then longer, periods can skip a month or two and come back, and bleeding can be heavier or lighter than before. That's expected, but some bleeding changes should always be checked.
In short
- Ovulation becomes less regular in perimenopause, so cycle length and bleeding change.
- Skipped periods are common. Menopause is only reached after 12 months in a row without a period.
- Bleeding between periods, after sex, very heavy bleeding or any bleeding after 12 months without periods needs a doctor.
Why do periods become irregular in perimenopause?
Because ovulation becomes less reliable. Some months you ovulate, some months you don't, and estrogen and progesterone rise and fall unevenly. The European Menopause and Andropause Society (EMAS) describes the menopausal transition as the time before the last period when the menstrual cycle usually becomes more variable.
What changes are normal?
Cleveland Clinic lists typical changes in perimenopause:
- cycles that are longer one month and shorter the next
- periods that are shorter or longer than usual
- skipping a month or two, then going back to monthly periods
- periods spreading out, for example every two to three months
- flow that is lighter one time and heavier the next
See also Things nobody tells you about perimenopause.
Can I still get pregnant with irregular periods?
Yes. As long as you have periods, you may still ovulate. If you don't want to get pregnant, keep using contraception until your doctor says it's safe to stop. A missed period can also mean pregnancy, so a test is worth doing if in doubt.
When is it menopause?
Only after 12 months in a row without a period, with no other cause. Because periods can return after several months, you only know in hindsight. More in Perimenopause vs menopause.
What else can cause irregular periods?
Not every change is perimenopause. Pregnancy, hormonal contraception, fibroids and some medicines or health conditions can also change your bleeding. That's why new or unusual bleeding is worth discussing with your doctor.
When to see a doctor
See your doctor if your periods are much heavier than before, last longer than usual, come very close together, or if you bleed between periods or after sex. EMAS notes that abnormal bleeding in perimenopause should be assessed. Read more in Heavy periods in perimenopause.
Always get checked if you have any bleeding after 12 months without a period, even if it happens once or is very light.
Bring a record of your period dates and how heavy each one was, on paper or in an app like Pausie. It shows your doctor the pattern far better than memory.
Frequently asked questions
How irregular can periods get in perimenopause?
Very. Some women skip several months and then have a period again. What matters more is the kind of bleeding: very heavy bleeding, bleeding between periods or after sex should be checked.
Can periods come every two weeks in perimenopause?
Cycles can get shorter, but periods that come very close together should be checked by a doctor.
I haven't had a period for 6 months. Am I in menopause?
Not yet. Periods can still return. Menopause is confirmed after 12 months without one.
Do I need a blood test?
Usually not if you're over 45. Your doctor may suggest tests to rule out other causes.
Let your calendar keep count
Pausie is built for irregular cycles: log period days and how heavy they are, and in perimenopause it counts the days since your last period for you. No account, and your diary stays on your phone.
This article is general information, not medical advice. Written by the Pausie team. Published and last reviewed 2 November 2026.
Sources
- EMAS Menopause Essentials: Technical definitions of menopause terms
- EMAS Menopause Essentials: Assessing perimenopausal and postmenopausal bleeding
- Cleveland Clinic: Do my period changes mean perimenopause?
- Cleveland Clinic: Perimenopause
- WHO: Menopause fact sheet
- NHS: Symptoms of menopause and perimenopause