Although heavy periods are common, in most cases no cause will be found. In some cases the cause is a medical condition such as endometriosis or fibroids. For the majority of patients, treatment is effective through medication to reduce bleeding, or surgery.
It can be difficult to know if your periods are normal or heavy compared with other women. A heavy period is generally blood loss of 60-80 ml or more, but it is difficult to measure how much blood you lose during a period.
Your period could be defined as heavy if you:
- Pass large blood clots
- Require frequent changes of tampons or sanitary towels
- Require double sanitary protection (tampons and sanitary towels)
- Bleed through to clothes or bedding
Heavy periods that recur each month, and interfere with your quality of life, are known as menorrhagia. Menorrhagia accounts for 30% of all Gynaecological outpatient attendances. 25% of women feel that their menstrual loss is excessive and up to 10% take time off work.
Causes Of Heavy Periods
In 40-60% of cases the cause of heavy bleeding is not known. This is called dysfunctional uterine bleeding. With dysfunctional uterine bleeding, the womb and ovaries are normal, it is not a hormonal problem, and periods may be regular. This condition is more common in patients approaching the menopause or who have only started their periods recently (in these cases periods are likely to be irregular in addition to being heavy).
Other, less common causes of heavy bleeding include:
- Fibroids, which are non-cancerous tumours that grow in the muscle of the uterus
- Endometriosis, where cells from the uterus lining grow in other parts of the body
- Pelvic infection (e.g. STIs)
- Polyps, masses in the inner lining of the uterus
- Endometrial cancer (very rare cause)
- Hormonal problems
- Polycystic ovary syndrome
- Anticoagulant medication such as warfarin
To diagnose the cause of heavy periods, tests may include a vaginal examination of the cervix (neck of the womb) and examination of the size and shape of the uterus (womb). If the vaginal examination is normal and the patient is under 40 years old, the diagnosis is generally dysfunctional uterine bleeding. If the uterus is found to be large or abnormal, and/or they are over 45 years old, further diagnostic tests may be required. Further tests will also be required if other symptoms, such as irregular bleeding or pain during sex, are also present. These may include:
- Ultrasound, which can detect fibroids, polyps or structural changes in the uterus
- Internal swabs to check for infection
- Hysteroscopy (a thin telescope is passed into the uterus)
- Endometrial sampling (biopsy of the uterine lining) to check for abnormalities
Most patients are given a blood test to check for anemia, due to the heavy blood loss. Approximately 60% of women with menorrhagia (recurrent heavy periods) will develop anemia.