Effects on the endometrium, endo- and exocervix following the use of local progestogen-releasing delivery systems

Some conflicting reports have appeared in the literature as to the effect of progestogens on the endometrium and on the endo- and exocervix in animals and humans. Hyperplasia of the endometrial and endocervical epithelium has been reported in some non-human primates following the administration of progestogens. In other studies no evidence has been found for such changes. In women using combined oral contraceptives, it has been claimed that the progestogen component causes adenomatous hyperplasia of the endocervix and that this hyperplastic transformation could be a precursor to adenocarcinoma of the cervix. So far, there is, however, no evidence in the literature to confirm this hypothesis. In view of the development of new delivery systems with a constant release of small amounts of progestogens, previous reports in the literature on hyperplasia and potential malignant transformation of the endometrium and the endocervix have been a matter of concern. The aim of the present study is therefore to review results from studies in animals and humans in particular with reference to the effect of a local release of various progestogens on the endometrium and the endo- and exocervix.