Hesperian Health Guides

Abnormal Menstrual Bleeding

In this chapter:

Menstrual periods with heavy bleeding

Periods with heavy bleeding are uncomfortable and having them often can lead to anemia. Signs include:

  • The menstrual flow soaks through your pad, cloth, or tampon every hour for several hours in a row.
  • Menstrual periods last more than a week.
  • Blood clots (dark red shiny lumps) larger than 2½ cm (1 inch).
  • Heavy flow stops you from going places or doing what you usually do.

Possible causes of heavy bleeding include:
  • changes in the hormones that control your menstrual cycle, more likely if you just started having menstrual periods, were pregnant or stopped breastfeeding recently, or are close to menopause.
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  • a problem with your thyroid gland.
  • Miscarriage, even if you did not think you were pregnant.

Menstrual periods with light bleeding

Light bleeding each month is not a health problem itself but may be a sign of a medical problem.

Possible causes:

Menstrual periods that come too often or bleeding at other times

Your menstrual cycles will not always be regular. But if your cycle was regular and has changed, or if your periods come more often than every 3 weeks, see a health worker.

Possible causes:

Hormonal family planning methods, such as pills, implants, or injections, can change your menstrual periods in different ways.

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Menstrual periods that come too far apart or have stopped

Menstrual periods usually come about every 21 to 35 days, though some people have periods less often. But if your period is later than usual or does not come at all, you may be pregnant or have a serious medical problem. See a health worker.

Most people have their first menstrual period between ages 10 to 16. Not getting enough to eat and some illnesses can delay this. If you are over 16 and your periods haven’t started, talk to a health worker.

Possible causes:

This page was updated:13 Nov 2023