Heavy menstruation (Menorrhagia)

1. How is menstruation considered ‘heavy’?

  • For research and study purpose, menstrual blood loss is accurately measured and heavy menstruation (termed ‘menorrhagia’) is defined as blood loss >/=80 ml.
  • However, it is difficult to measure menstrual blood loss accurately outside the research setting. If one experiences some of the followings, one may have had menorrhagia:
  1. (i) Soak through sanitary pads or tampons every hour for several hours
  2. (ii) Need to change sanitary products every hour
  3. (iii) Need to use double sanitary protection 
  4. (iv) Pass blood clots larger than 2.5cm in size
  5. (v) Period longer than 8 days
  6. (vi) Symptoms of anaemia, e.g. dizziness, fatigue and shortness of breath
  •  From the clinical point of view, one would need treatment if the menstruation has resulted in the followings:
  1. (i) Iron deficiency anaemia
  2. (ii) Restriction of daily activities (e.g. could not leave home, absence from work)

2. Causes for menorrhagia

  • Problems with the uterus
  1. (i) Fibroid(s)
  2. They are benign tumours arising from the muscle wall of the uterus. It is estimated that 1 in 3 women will have fibroid(s) at some point in their life. They are most commonly found in women aged 30-50. 
  3. (ii) Adenomyosis
  4. It is a condition when the lining of the uterus (endometrial tissue) has grown into the muscular wall of the uterus. This results in enlargement of the uterus and may cause painful and heavy menstruation. It is most commonly found in women aged 35-50.  
  5. (iii) Endometrial polyp / fibroid polyp
  6. Endometrial polyp is an outgrowth of cells from the endometrial lining which extends to the uterine cavity. It typically causes abnormal uterine bleeding and occasionally can cause menorrhagia. 
  7. Endometrial fibroid polyp is fibroid which extends inside the uterine cavity in the form of a polyp. It can cause heavy and prolonged menstruation.
  8. (iv) Cancer of the uterus
  9. Uterine cancer typically causes prolonged vaginal bleeding rather than regular heavy menstruation. It is uncommon (though still possible) in women aged below 40. The average age at diagnosis is 60. (Please see the section on ‘Cancer of uterus’ for details)
  10. (v) Pregnancy related problems
  11. Pregnancy complications like miscarriage may cause prolonged vaginal bleeding, which might be mistaken as menorrhagia by some women.
  • Iatrogenic causes
  1. (i) Intrauterine contraceptive device (IUCD)
  2. Copper IUCD may cause heavier menstruation. Mirena (Progestogen) IUCD can be used to treat menorrhagia but at the first 4-6 months of insertion, it may result in prolonged and irregular menstruation. 
  3. (ii) Medication for thinning the blood e.g. anti-coagulants
  • Generalised bleeding disorders
  • No cause found
  1. Sometimes no pathology can be identified for menorrhagia. It is called ‘dysfunctional uterine bleeding’. 

3. Investigations

History is very important to find out the bleeding pattern and any possible underlying causes like IUCD or medication, etc. Physical examination should look for enlarged uterus or pelvic mass. The basic investigations include a blood test to look for anaemia, cervical smear to exclude cervical cellular changes and pelvic ultrasound for possible uterine pathology. Further tests like pregnancy test, thyroid function, endometrial biopsy are arranged if indicated.

4. Management of menorrhagia

The management depends on the underlying cause and the severity of the condition. Milder cases are usually managed with medical means first, including iron supplement and medication to reduce the amount of bleeding. Sometimes, Mirena IUCD may help to treat menorrhagia. For severe anaemia or those who fail to respond to medical treatment, surgical means would be appropriate.

This article is contributed by Dr. T.N. Danny Leung
updated on 15.11.2023