IN BRIEF: Most menstrual periods last between three and seven days and become lighter in the last two days. A total blood loss of between 60 and 250ml (two tablespoons to about one cup) usually occurs.

However, up to 10 per cent of women experience prolonged menstrual periods lasting up to several weeks, or particularly heavy periods with flooding and passing of blood clots. This is called menorrhagia.

Menorrhagia is particularly common in women approaching menopause. A single, particularly heavy menstrual period may also be a sign of a miscarriage – consult your doctor if an unusually heavy menstrual flow does not subside within 24 hours.

In other cases, menorrhagia can be a sign of disease or injury to the vaginal opening, cervix or uterus. As ongoing blood loss can result in iron deficiency anaemia, and bleeding may signal an underlying disorder, you should consult your doctor if you have any concerns about your pattern of menstrual periods.

Causes of heavy periods may include:

• Injury or disease of the vaginal opening, including infections, polyps, genital warts, ulcers or varicose veins
• Vaginal injury from an infection, malignancy (cancer) or the insertion of foreign objects
• Abnormal pregnancy, such as an ectopic pregnancy (the fertilised egg develops in the fallopian tubes, instead of in the uterus)
• Use of an Intra Uterine Device (IUD) – also known as a coil, which is inserted through the cervix for contraception
• Fibroids (benign tumours of the uterus)
• Pelvic infection (an infection of the uterus and/or fallopian tubes)