[From embryogenesis to pathogenesis of effects of diethylstilbestrol on the female genital tract].

From studies on embryogenesis, the authors describe the development, not conditioned by sex steroids, of the upper female genital tract and, in particular, the formation of its cervico-vaginal portion and the shaping of the uterine cervix in about the 16th week of pregnancy. Basing themselves on the physiology of the foeto-placental unit and on the hormonal profile of the foetal ovary, they show that the action of oestrogens on the foetal uterine cervix can be observed only from the 32nd week onward. The action of diethylstilboestrol--a potent oestrogen that is not steroidal and therefore not degraded by foetal metabolism--on the foetal genital tract is explained. An excessive development of the uterine canal caudal part determines structural anomalies of the uterine cervix at birth, the T shape of the uterine cavity and the vaginal diaphragms. The aetiogenesis of clear-cell adenocarcinoma in the cervico-vaginal portion is discussed.