Heavy periods: how much bleeding is too much?

How much period bleeding is normal?

A period usually lasts 2 to 7 days, and the heaviest bleeding is often in the first 2 or 3 days. Over a whole period, most people lose about 1 to 5 tablespoons (20 to 90 ml) of blood.

It often looks like more than it is. That's why doctors ask about how often you change products, not how much blood you think you lost.

What are the signs of heavy menstrual bleeding?

Heavy menstrual bleeding (once called menorrhagia) is common, and for some people it's normal for them. You may have heavy periods if you:

• Change your pad or tampon every 1 to 2 hours, or empty your menstrual cup more often than recommended.
• Need to use two products together, like a pad and a tampon.
• Bleed for more than 7 days.
• Pass clots larger than a quarter, about 1 inch (2.5 cm) across.
• Bleed through to your clothes or bedding, or wake at night to change.
• Skip work, school or exercise because of your period.
• Feel tired, weak or short of breath a lot.

What causes heavy periods?

Periods can be heavier at certain times, like in the first years after they start, after pregnancy and in the years before menopause. Sometimes there's an underlying cause:

• Problems with ovulation, which can let the uterine lining get too thick, for example with PCOS or an underactive thyroid.
• Fibroids or polyps, non-cancerous growths in the uterus.
• Adenomyosis or endometriosis.
• Bleeding disorders, like von Willebrand disease, which make it harder for blood to clot.
• Some medicines, like blood thinners, and the copper IUD, especially in its first year.
• Pelvic inflammatory disease, an infection of the reproductive organs.
• Pregnancy-related bleeding, like a miscarriage.
• Rarely, cancer of the uterus, which is more common after menopause.

Could heavy periods be a bleeding disorder?

Heavy periods are the most common sign of a bleeding disorder in women and girls, but having heavy periods doesn't mean you have one.

Tell your doctor if your periods have been heavy since they started, or if you also bruise easily, get frequent nosebleeds, bleed a lot after dental work or surgery, or have family members with clotting problems.

Can heavy periods cause anemia?

Yes. Losing a lot of blood each month can lower your iron, which can lead to iron-deficiency anemia. Your blood then carries less oxygen.

Signs include feeling tired, weak, dizzy or lightheaded, or being short of breath. A simple blood test can check your iron levels.

How are heavy periods treated?

Heavy periods don't always need treatment, but many options can help if they affect your life. What fits depends on the cause, your health and whether you want to get pregnant.

A doctor may talk with you about hormonal options like a hormonal IUD or the pill, a non-hormonal medicine called tranexamic acid, or anti-inflammatory medicines. If these don't help, procedures to treat fibroids or the lining of the uterus are options. Ask your doctor about the pros and cons of each.

How can I track how heavy my period is?

Before your visit, keep a record for a few cycles. Note the dates you bleed, how many pads or tampons you use each day, how soaked they are, any clots and any night-time changes.

This gives your doctor a clear picture and helps them decide which tests you need, like blood tests or an ultrasound.