Disorders of menstruation present a significant burden to health services. Furthermore, hysterectomy, the definitive surgical treatment for menorrhagia, is the most common major operation performed on women of reproductive age in Britain and America [1–3]. Heavy menstrual bleeding may be the result of organic disease such as fibroids, infection or malignancy, but in most cases, no such underlying lesion can be found and the diagnosis of dysfunctional bleeding is made. In some circumstances, and especially at the extremes of the reproductive career, dysfunctional bleeding may be the result of anovulation [4,5]. However, in most women with regular but heavy periods no abnormality of the hypothala-mopituitary axis can be demonstrated, and the abnormality is therefore thought to lie at the level of the endometrium itself [6].