Irregular periods in perimenopause: what's normal, what isn't

How cycles typically change, stage by stage

Researchers describe the transition with the STRAW+10 staging system, and it maps well onto lived experience. Early perimenopause: cycles still arrive but their length varies by seven or more days — a 26-day month, then 35, then 29. Late perimenopause: gaps of 60 days or more appear. Menopause itself is only defined afterwards, once 12 consecutive months have passed with no period.

Flow commonly changes too: heavier and longer in the early years (often when cycles skip ovulation), then typically lighter and more spaced out toward the end.

Bleeding patterns that need prompt attention

Most irregularity is the transition doing what it does. These patterns are the exceptions — none of them should be waved off as 'just perimenopause' without an assessment:

• Bleeding heavy enough to soak a pad or tampon every hour for several hours
• Periods lasting longer than 7 days, or clots larger than a quarter
• Bleeding or spotting between periods that keeps happening
• Bleeding after sex
• Cycles consistently shorter than 21 days
• Any bleeding after 12 months without a period — always warrants a consultation

Why tracking beats memory

The single most useful thing you can bring to an appointment is a record: dates, cycle length, flow, and any symptoms alongside. Clinicians assess perimenopause largely from the cycle pattern, and six months of notes turn a vague story into a diagnosable one. A paper calendar works as well as any app.

You can still get pregnant

Irregular does not mean infertile. Ovulation still happens unpredictably through perimenopause, so contraception remains necessary until menopause is confirmed — the usual guidance is 12 months without a period if you are over 50, and 24 months if you are under 50. Which method fits alongside perimenopause symptoms is itself worth a conversation with a clinician.

When to see someone

See a clinician promptly for any of the red-flag patterns above. Beyond those, book a consultation if irregularity comes with symptoms that interfere with your life — heavy bleeding causing fatigue, sleep loss, mood changes — or simply if you want to understand where you are in the transition. A practitioner who focuses on menopause care will read a cycle log fluently.