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 30-40 millilitres (ml), with 9 out of 10 women losing less than 80ml. 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

What causes heavy periods?

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

• uterine fibroids
• intrauterine contraceptive devices (IUDs) 
• anticoagulant medication
• polycystic ovary syndrome (PCOS)

Read more about the causes of heavy periods.

Diagnosing heavy periods

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

The cause of the problem may sometimes need to be investigated further. This will usually involve having a pelvic examination. A blood test may also sometimes be recommended to check for anaemia (iron deficiency).

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.