There has been some confusion among women and health professionals since the publication of the Women's Health Initiative and Million Women studies about the management of premature ovarian failure (POF). Both studies were undertaken in women aged 50 and over, and cannot be extrapolated to their younger counterparts, who would normally be producing their endogenous estrogen, since they have functioning ovaries. Estrogen-based replacement therapy is the main stay of treatment for women with POF and is recommended at least until the average age of natural menopause (52 years in the UK). This view is endorsed by regulatory bodies such as the Committee on Safety of Medicines (now the Commission on Human Medicines) in the UK. No evidence shows that estrogen replacement increases the risk of breast cancer to a level greater than that found in normally menstruating women, and women with POF do not need to start mammographic screening early unless other risk factors are present, such as family history.