Heavy menstrual bleeding: how much is too much, and what can help
Signs your periods are heavy
Everyone's 'normal' is different, and it's hard to measure blood loss at home. Doctors focus on how much your periods affect your life. Signs that your bleeding may be heavy include:
- Changing your pad or tampon every one to two hours, or emptying a menstrual cup more often than recommended
- Using two types of protection together, such as a tampon and a pad
- Bleeding through to your clothes or bedding, or having to get up in the night to change
- Passing blood clots larger than about 2.5cm (roughly the size of a large coin)
- Bleeding for more than seven days
- Planning your life around your period, or avoiding work, school or activities
- Feeling tired, short of breath or dizzy, which can be signs of iron deficiency
What causes heavy periods?
Sometimes heavy periods happen without any clear cause. Other times, they're linked to:
- Hormone changes, for example in the teenage years or perimenopause
- Fibroids — non-cancerous growths in or around the womb
- Polyps in the womb lining
- Adenomyosis — when womb lining tissue grows into the muscle wall of the womb
- Endometriosis
- PCOS
- A copper coil (IUD), which can make periods heavier for some people
- Some medicines, such as blood thinners
- An underactive thyroid
- Bleeding disorders, such as von Willebrand disease, especially if you've had heavy periods since your first one, or bleed easily in other ways
- Rarely, womb cancer, which is more likely after age 45 and when there's other unusual bleeding
This is why it's worth getting heavy periods checked rather than assuming they're just how you are.
What to expect at the doctor
Your doctor will ask about your periods, how they affect your life and your general health. It helps to bring a record of a couple of cycles — how many days you bleed, how often you change products and whether you pass clots or flood.
They may suggest:
- a blood test to check for iron deficiency anaemia
- a pelvic examination
- an ultrasound scan to look for fibroids or other changes
- tests for thyroid or bleeding disorders if relevant
- referral to a specialist, sometimes for a camera test of the womb (hysteroscopy) or a sample of the womb lining
Treatment options
There's a range of effective treatments, and the right one depends on the cause, your health and whether you want to get pregnant:
- A hormonal coil (IUS), which often makes periods much lighter
- Non-hormonal tablets taken during your period to reduce bleeding
- Anti-inflammatory painkillers, which can reduce bleeding and pain for some people
- Hormonal contraceptives, such as the combined pill
- Other hormone treatments
- Procedures or surgery, such as removing fibroids or polyps, or treatments to the womb lining for people who don't want future pregnancies
If you're low in iron, your doctor may also recommend treatment for that. Don't put up with heavy periods because you think nothing can be done.
When to get help urgently
Seek urgent medical care if:
- you're soaking through a pad or tampon every hour for several hours in a row
- you feel dizzy, faint, very weak, breathless or have chest pain or a racing heart
- you have heavy bleeding and you're pregnant or might be
- you have severe pain with the bleeding
See a doctor soon if you have bleeding between periods, after sex or after menopause, or if your periods have suddenly become much heavier than usual.
Frequently asked questions
Are blood clots in your period normal?
Small clots can be normal, especially on heavier days. Clots larger than about 2.5cm, or frequent clots, can be a sign of heavy periods and are worth mentioning to a doctor.
Can heavy periods make you tired?
Yes. Losing a lot of blood each month can lead to iron deficiency anaemia, which can cause tiredness, shortness of breath, headaches and pale skin. A simple blood test can check your iron levels.
Why are my periods suddenly heavier?
Periods can become heavier during perimenopause, after stopping hormonal contraception or with a copper coil, but sudden changes can also be caused by fibroids, polyps or other conditions. If it's new or keeps happening, get checked.
How long is too long for a period?
Bleeding for more than seven days is generally considered prolonged. If this happens regularly, or alongside heavy flow, see a doctor.
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This guide is general information written to help you understand your options. It is not a substitute for advice from a doctor, lawyer or financial adviser who knows your situation — if you have worrying symptoms, please see a health professional.