Abnormal uterine bleeding imposes major medical, social and financial problems for women, their families and the health services. Abnormal uterine bleeding refers to the regularity, frequency, duration and volume of bleeding. Irregular menstrual bleeding is most common at the extremes of reproductive life, in the initial 12-18 months after menarche and 5-6 years before the menopause begins. In Australia, the estimated cost of investigating and managing heavy menstrual bleeding alone is approximately AUS $6 million per annum. This article addresses the common causes of irregular bleeding in pre- and peri-menopausal women and presents an investigational approach.