Two-hundred and ninety-three patients without a previous vaginal delivery were randomized to intracervical/extra-amniotic application of 0.5 mg prostaglandin E2 (PGE2) or to gel only. Of the patients who received PGE2, 18.7% were admitted before the next morning due to spontaneous abortion, bleeding or pains. No other side-effect was observed. A statistically significant dilatation of the cervical canal was found in the prostaglandin group. Thirty percent of the treated patients did not need further dilatation of the cervix 25.4% were non-responders to PGE2 and 7.7% were hyper-responders. The number of uterine perforations, pelvic inflammatory disease (PID) or retained pregnancy products were not influenced by the pretreatment with PGE2.