Heavy periods, also called menorrhagia, is when a woman loses an excessive amount of blood during consecutive periods.

Menorrhagia can occur by itself or in combination with other symptoms, such as menstrual pain (dysmenorrhoea).

Heavy bleeding does not necessarily mean there is anything seriously wrong, but it can affect a woman physically, emotionally and socially, and can cause disruption to everyday life.

See your GP if you are worried about heavy bleeding during or between your periods.

How much is heavy bleeding?

It is difficult to define exactly what a heavy period is because the amount of blood lost during a period can vary considerably between women.

The average amount of blood lost during a period is 30-40ml (millilitres), with nine out of 10 women losing less than 80ml. Therefore, heavy menstrual bleeding is considered to be 60-80ml or more in each cycle.

However, it is rarely necessary to measure blood loss. Most women have a good idea about how much bleeding is normal for them during their period and can tell when this amount increases or decreases.

A good indication that your blood loss is excessive is if:

  • you feel you are using an unusually high number of tampons or pads
  • you experience flooding (heavy bleeding) through to your clothes or bedding
  • you need to use tampons and towels together

Why do heavy periods happen?

In most cases, no underlying cause of heavy periods is identified. However, some conditions and treatments have been linked to menorrhagia, including:

Read more about the causes of heavy periods.


Your GP should be able to diagnose heavy periods from your symptoms alone.

The cause of your menorrhagia may sometimes need to be investigated further. Usually, this involves a pelvic examination and a blood test.

If a cause is still not found, then you may have an ultrasound scan.

Read more about diagnosing heavy periods.

Treating heavy periods 

In some cases, heavy periods do not need to be treated, as they can be a natural variation and may not disrupt your lifestyle.

If treatment is necessary, medication is most commonly used first. However, it may take a while to find the medication most suitable for you, as their effectiveness is different for everyone and some also act as contraceptives.

If medication doesn't work, surgery may also be an option.

Read more about treating heavy periods.

What are periods?

period is part of a woman's menstrual cycle. The menstrual cycle is the time from the first day of a woman's period to the day before her next period. A period is a bleed from the womb (uterus) which is released through the vagina. It happens approximately every 28 days, although anywhere between 24 and 35 days is common.

Periods can begin when girls are between eight and 16 years of age, but usually start around 12 years of age. They continue every month until the menopause (when a woman's periods stop), which usually occurs between 45 and 55 years of age.

Page last reviewed: 10/10/2012

Next review due: 10/10/2014