How much bleeding is too much?

Key takeaways

Changing your pad or tampon every one to two hours, or bleeding for more than seven days, can be signs of heavy periods.
Heavy periods are common and often have no serious cause, but they can lead to iron deficiency and should be checked.
Effective treatments exist, such as a hormonal coil or non-hormonal tablets, so you don't have to just put up with it.

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Your periods may be heavy if you need to change your pad or tampon every one to two hours, use two types of protection at once, bleed through to your clothes or bedding, pass clots larger than about 2.5cm, or bleed for more than seven days. Heavy periods are common and often have no serious cause, but they can lead to iron deficiency and can sometimes be caused by conditions like fibroids or endometriosis. If heavy bleeding affects your daily life, see a doctor, because effective treatments are available.

Read: Heavy menstrual bleeding: how much is too much, and what can help

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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.

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