Heavy menstrual bleeding: definition and meaning
Heavy menstrual bleeding is period blood loss heavy enough to interfere with your physical, social or emotional life. In research it means losing more than 80 ml per period, but doctors now go mainly by impact: changing products every hour or two, flooding, large clots or bleeding over 7 days. It affects up to 1 in 3 people at some point.
Signs your bleeding is heavy
- Soaking a pad or tampon every 1 to 2 hours for several hours
- Needing to double up products or get up at night to change
- Passing clots bigger than a quarter (2.5 cm)
- Bleeding longer than 7 days
- Leaking through clothes or bedding, or avoiding plans because of it
- Feeling tired, short of breath or dizzy
Common causes
| Cause | Notes |
|---|---|
| Fibroids and polyps | Very common, especially 30s to 40s |
| Adenomyosis | Heavy and painful periods |
| Hormone changes | Teens, perimenopause, anovulation |
| Bleeding disorders | Such as von Willebrand disease; often heavy since the first period |
| Copper IUD, blood thinners | Can increase flow |
Why it matters
Heavy bleeding is a leading cause of iron deficiency anemia, which can leave you exhausted, foggy and low in mood. Treatments work well: a hormonal IUD, tranexamic acid, NSAIDs, the pill, or procedures. Read the full guide: heavy periods, and what is a heavy period.
See a doctor if heavy periods affect your daily life. Get urgent care if you soak a pad every hour for more than two hours, feel faint, or have heavy bleeding in pregnancy or after menopause.
Frequently asked questions
Is menorrhagia the same as heavy menstrual bleeding?
Yes, menorrhagia is the older medical term. Many guidelines now use heavy menstrual bleeding instead.
Can heavy periods affect mood?
Yes. The tiredness from blood and iron loss, plus the stress of managing leaks, can lower mood and energy.
Sources
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
Keep reading
Heavy periods: what counts as heavy and what helpsHow to tell if you have heavy periods: soaking a pad every hour or two, clots, bleeding over 7 days. Causes, treatments that work, and when to get help.What counts as a heavy period?What is a heavy period? Soaking a pad or tampon every 1 to 2 hours, clots bigger than a quarter, or bleeding over 7 days. A quick self-check.What is menorrhagia?Menorrhagia is the medical term for heavy or prolonged periods, now usually called heavy menstrual bleeding. Signs, causes, and when to see a doctor.
Iron deficiency anemia: definition and meaningIron deficiency anemia is when low iron means your blood can't carry enough oxygen. Why heavy periods cause it, the symptoms, and what to ask your doctor.
Menstrual flow: definition and meaningMenstrual flow is how much you bleed during a period. What counts as light, medium and heavy flow, how much blood is normal, and when to see a doctor.