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Irregular periods are often the first sign of perimenopause. Learn which changes are expected, which bleeding needs checking, and how to manage your cycle.
Irregular periods are usually the first sign of perimenopause. Cycles may become shorter or longer, periods may be heavier, lighter or skipped, and spotting can happen. This happens because ovulation becomes less predictable. Some changes need checking, though: bleeding after sex or between periods, very heavy or prolonged bleeding, or any bleeding a year after your last period.
Changes vary from person to person and can shift over time. Common patterns include:
ACOG notes that during perimenopause, periods may become shorter or longer, the days between them may increase or decrease, and bleeding may become heavier or lighter.
During perimenopause, the ovaries respond less consistently to signals from the brain. Some months the ovaries release an egg; other months they don’t. Estrogen fluctuates, sometimes rising higher than usual, while progesterone falls in cycles without ovulation.
Without the regular rise and fall of progesterone that follows ovulation, the womb lining can build up unevenly and shed unpredictably. That’s why periods can be late, early, heavy, light or skipped. See hormone changes during perimenopause.
The STRAW+10 research framework describes two stages of perimenopause based on bleeding patterns:
| Stage | Typical pattern |
|---|---|
| Early perimenopause | Cycle length changes by 7 days or more, and this recurs within 10 cycles |
| Late perimenopause | At least one gap of 60 days or more without a period |
| Menopause | 12 months with no period |
Not everyone follows this neatly. Research summarized by the US Centers for Disease Control and Prevention found 12% to 25% of women have little or no change in cycle length before their final period. See the stages of menopause.
Perimenopause is common in the 40s, but other causes should be considered, especially if changes are sudden or unusual:
See perimenopause or something else.
Many changes are expected, but some need assessment.
See a clinician promptly if you have:
- Bleeding after sex
- Bleeding or spotting between periods that keeps happening
- Very heavy bleeding: soaking through one or more pads or tampons every hour for several hours, needing to double up protection, or passing large clots
- Periods lasting more than 7 days
- Periods coming more often than every 21 days
- Any bleeding 12 months or more after your last period
- Heavy bleeding with tiredness, breathlessness or dizziness, which may signal anemia
Seek emergency care if you’re soaking through pads or tampons every hour for more than 2 hours and also have chest pain, breathlessness or dizziness.
The Australasian Menopause Society notes that heavy bleeding, bleeding after a long gap, and prolonged bleeding of any amount should be investigated. Any bleeding after menopause also needs checking.
A clinician will usually ask about:
Depending on your symptoms, they may suggest:
For people over 45 with irregular periods and other menopause symptoms, NICE advises no hormone tests are needed to identify perimenopause.
Treatment depends on what bothers you and your contraception needs:
See heavy bleeding for more detail.
A simple record makes it far easier to tell expected changes from ones that need checking:
| What to record | Example |
|---|---|
| First day of each period | 3 March, 24 March, 2 May |
| Number of bleeding days | 5 days, then 9 days |
| Heaviness | Light, medium or heavy; how often you changed protection; clots |
| Spotting between periods | Date, and whether it happened after sex |
| Other symptoms | Hot flashes, pain, tiredness, mood |
Our private Symptom Explorer can store this for you and prepare a summary for your appointment.
"Irregular periods mean I can’t get pregnant." You can, until guidance says you can stop contraception.
"Any bleeding in perimenopause is normal." Many changes are expected, but bleeding after sex, between periods, very heavy bleeding, or bleeding after menopause needs checking.
"If my periods are regular, I’m not in perimenopause." Some people have little change in their cycle before their final period, and notice other symptoms first.
"Irregular periods always mean menopause is close." Irregular cycles can continue for several years before the final period.
Heavy bleeding · Hot flashes · Fatigue
See the early signs of perimenopause.
Shorter cycles are common in perimenopause. However, periods more often than every 21 days, or bleeding between periods, should be checked.
Yes. Periods can stop for months and then return. This is why menopause is only confirmed after 12 months without a period.
Brown blood is usually older blood that has taken longer to leave the body, and it’s common with lighter or irregular periods. Persistent unusual discharge or bleeding should be checked.
Yes. Ovulation can still happen unpredictably, so use contraception until guidance says you can stop.
Not necessarily. UK guidance from the Faculty of Sexual and Reproductive Healthcare advises that clinicians focus on your symptoms and needs rather than hormone levels. Many contraceptive methods can be continued until contraception is no longer needed. Discuss your situation before stopping.
Bleeding after sex can have simple causes, such as vaginal dryness, but it can also be caused by problems with the cervix or womb lining. It should always be checked.
Editorial status: evidence-based educational article; not individually medically reviewed. Last evidence check: September 10, 2026.
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