Abstract
A prospective study of 745 women receiving different regimens of hormone treatment for the climacteric for a total of 21 736 months was performed. There was a lower incidence of endometrial hyperplasia in biopsy specimens in the women receiving cyclical low-dose oestrogen by mouth than in those receiving cyclical high-dose oestrogen by mouth. The incidence of abnormalities in the women receiving sequential oestrogen and progestogen was lower than in either of these two groups. Among the women receiving subcutaneous oestrogen implants the incidence was higher still, but over half of the abnormal specimens were from women who had not taken their progestogen. The incidence of hyperplasia fell with longer courses of progestogen, and no hyperplasia was found in patients taking progestogen for over 10 days each month. The incidence of adenomatous and atypical hyperplasia is significantly reduced by a progestogen when taken for 10 or more days monthly. The absence of vaginal bleeding or of a regular bleeding response does not guarantee histologically normal endometrium in patients taking oestrogens without progestogen.