How to recognise heavy bleeding
The UK's National Health Service (NHS) lists these signs:
- changing your pad or tampon every one to two hours
- needing two period products at the same time
- periods lasting longer than seven days
- blood clots larger than about 2.5 cm
- bleeding through to clothes or bedding
- avoiding exercise or daily activities, or taking time off
- often feeling tired or short of breath
Why it's more than a nuisance
Heavy menstrual bleeding is one of the main reasons for iron deficiency in women, with and without anaemia. A 2023 review describes both as common and often dismissed as normal – by those affected as much as in doctors' surgeries. Both cost quality of life: the bleeding on the days of your period, the iron deficiency every day.
Why a normal blood count isn't enough is explained in our article on iron deficiency without anaemia.
What can be behind it
A 2025 meta-analysis of more than 41,000 patients looked at which causes were found behind heavy periods. A bleeding disorder, such as von Willebrand disease, was present in 30% overall: 39% of adolescents and 16% of adults, though the adult figure is very uncertain. Thyroid disorders (3%) and polycystic ovary syndrome (PCOS, 8%) also occurred.
Heavy bleeding is also one of the common symptoms of endometriosis.
The NHS also lists fibroids, adenomyosis, pelvic inflammatory disease and some medicines, such as anticoagulants. Rarely, heavy periods are a sign of womb cancer.
What treatment is available
Heavy bleeding doesn't always need treatment. If it limits your daily life, though, there are options. The NHS lists a hormonal coil (IUS) or the combined pill, tranexamic acid, which reduces bleeding, and certain prescription painkillers as first steps. If these don't work, specialist procedures are an option. Which one fits is something you decide with your doctor.