Heavy bleeding in periods

Also known as heavy menstrual bleeding or menorrhagia

Menorrhagia is the term given to menstrual periods that are long and heavy. It may involve periods last for longer than 7 days, and/or excessive bleeding with flooding or clots.

What is considered to be 'heavy' bleeding?

Women with menorrhagia lose 80ml or more of blood per period, compared with the usual loss of about 30-40ml.

If you are changing your tampon or sanitary pad more often than every hour, flooding or becoming anaemic, this is a good indication you have menorrhagia and you should see your doctor. 

If you think you have heavy periods, see your doctor for a proper assessment.

Causes of menorrhagia

Menorrhagia affects 10-15% of women. There are a number of different causes of menorrhagia. These are some of the common ones: 

  • hormonal imbalances
  • a bleeding disorder
  • fibroids
  • infection
  • IUDs (not including the intrauterine system Mirena, which is in fact a treatment option for menorrhagia)
  • polyps (small growths on the cervical or uterine wall)
  • endometriosis
  • polycystic ovarian syndrome
  • thyroid disease
  • liver or kidney disease
  • malignancy.


The main symptoms of menorrhagia are:

  • periods that last longer than seven days
  • flooding or clots
  • excessive bleeding of 80ml or more of blood per period.

f you have no periods (and think you should), painful periods or heavy periods, see your doctor for a check up and further advice.

Treatment for menorrhagia

The best treatment for you will depend on what is causing or contributing to your menorrhagia.  

Your doctor may prescribe medication to control the bleeding or suggest an intrauterine contraceptive device is placed to reduce bleeding. The main treatments include:

After three months, if bleeding has not settled, talk with your doctor about referral to a specialist to discuss further options. These can include: 

  • endometrial ablation
  • hysterectomy
  • other surgical options.


It is common to have a heavier period than normal from time to time. However, if you have heavy periods each month, one of the key things to watch out for is iron deficiency. You may also find it useful to track your periods each month using either a symptom diary or period app on your phone. 

One of the most common causes of iron deficiency is prolonged or heavy periods and this can leave you feeling tired and lacking energy. In some cases, this can even lead to anaemia.

Ask your doctor or nurse if you need a blood test to check your ferritin (iron) test and full blood count. 

  • The best source of iron in food is red meat.
  • Eat plenty of fresh vegetables and fruit as vitamin C helps iron absorption in your gut. 
  • If your iron is low, you may need to also take iron supplements.
  • Read more about iron and iron deficiency.

Learn more

Menstruation Kids Health NZ 
All about Menstruation (For Teens) Puberty and Periods - Nemours Foundation and Kidshealth2015
Menstruation Medline Plus and National Institute of Child Health and Human Development (NIH)2014
Menorrhagia in adolescents - Assessing Heavy Periods  Medicine Today, 2009

Credits: Editorial team.