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Quick answer
Periods are heavy if you need to change a pad or tampon every one to two hours, pass clots larger than about 2.5cm, bleed through clothes or bedding, or the bleeding affects daily life. Heavy periods are common and often have no clear cause, but fibroids, polyps, endometriosis and some conditions can contribute. Effective treatments exist.
- Changing every 1 to 2 hours, double-protecting, clots over 2.5 cm or flooding are signs of heavy periods.
- NICE says the impact on your life matters, not just the amount of blood.
- Effective treatments exist, including a hormonal coil, tranexamic acid and painkillers.
- They can cause iron deficiency, so tiredness is worth mentioning to a GP.
Key facts
- NHS signs of heavy periods include changing pads or tampons every 1 to 2 hours and passing clots bigger than about 2.5cm.
- NICE NG88 says treatment should be based on how bleeding affects your life, not on measured blood loss.
- Heavy periods can lead to iron deficiency anaemia, which causes tiredness and breathlessness.
Many people with heavy periods do not realise their flow is heavier than average, because it is all they have ever known. NICE says heavy periods should be judged by how much they affect your life, not just by measuring the blood. So if your period is getting in the way, it counts.
How do I know if my period is heavy?
- Changing your pad or tampon every 1 to 2 hours, or emptying a cup more often than recommended.
- Needing to use two products at once.
- Periods lasting more than 7 days.
- Passing blood clots bigger than about 2.5 cm (the size of a 10p coin).
- Bleeding through to clothes or bedding.
- Avoiding exercise or missing work or school because of your period.
- Feeling tired or short of breath a lot.
What causes heavy periods?
Heavy periods can be normal for you, and they often change at life stages like puberty, after pregnancy, or near menopause. The NHS says they can also be linked to conditions like PMOS (formerly PCOS), fibroids, endometriosis, adenomyosis or pelvic infection, to bleeding conditions such as von Willebrand disease, or to some medicines such as blood thinners. A copper coil can make periods heavier for the first year, says ACOG. Rarely, heavy periods can be a sign of womb cancer, which is one reason to get them checked.
What a GP will usually do
- Ask how your periods affect your life, and look at any tracking you have.
- Offer a blood count for all women with heavy periods, to check for anaemia (NICE).
- Not rush to scans or hormone tests. NICE says hormone tests are not needed, and treatment can often start without finding a cause first.
What treatments help heavy periods?
NICE suggests considering a hormonal coil (levonorgestrel IUS) first if no cause such as large fibroids has been found. It can take around 6 cycles to see the full benefit. Other options are tranexamic acid (a non-hormonal tablet taken during your period), anti-inflammatory painkillers such as mefenamic acid or naproxen, the combined pill, or progestogen tablets. If those do not work, you may be referred for tests or procedures. Heavy periods do not always need treatment, but you do not have to put up with them.
MythHeavy periods are just something you have to put up with.
The NHS and NICE both say effective treatments exist. Heavy periods can also cause iron deficiency, so tiredness is worth mentioning.
- Changing a pad every 5 hours
- Needing to change every 1 to 2 hours
- A period lasting 4 days
Show the answer
B. Needing to change every 1 to 2 hours
Needing to change every 1 to 2 hours is one of the NHS signs of heavy periods.
Questions people ask
How much bleeding is too much on a period?
Doctors focus on impact rather than exact amounts: if you change protection every hour or two, flood, pass large clots, or plan your life around your period, it counts as heavy and is worth discussing with a GP.
What should I track before seeing a GP about heavy periods?
For two or three periods, note how many days you bleed, how often you change pads or tampons, any flooding or clots, and whether you feel tired or dizzy.
Sources
Written by the Splash teamSources checked
This is general information, not medical advice. Splash can’t diagnose. If you’re worried, talk to a GP, pharmacist or sexual health clinic. In an emergency call 999 (UK) or 911 (US). How we write and check articles.