An occasional off cycle is normal, but frequently irregular periods can signal something worth understanding. Here are the common causes and the signs that mean you should see a clinician.
Common causes
- Stress, which can delay or skip ovulation
- PCOS, a leading cause of irregular cycles
- Thyroid problems (over- or under-active)
- Significant weight change, under-eating, or over-exercising
- Perimenopause, in your 40s and beyond
- Hormonal birth control or recently stopping it
When to see a doctor
See a clinician if your periods are consistently irregular, you go more than three months without one (and aren’t pregnant), bleeding is very heavy, or you have other symptoms like excess hair, severe acne, or difficulty conceiving. Track your cycles first — the data helps diagnosis.
What can help
Treatment depends on the cause: lifestyle changes, addressing thyroid or PCOS, or hormonal options. Don’t self-diagnose — a clinician can test and tailor a plan.
For readers in Europe
Across the EU, GDPR gives you strong rights over your health data, including the right to access and erase it. Availability of services and medicines varies by country.