29 cases of 3rd degree perineal rupture occured from 1962 to 1975 at the Städtische Frauenklinik and Hebammenlehranstalt Braunschweig and have been analysed retrospectively. Most of these were observed in the last five years. The increase is undoubtlessly related to the shorter expulsion peried by ocytocin infusion. Investigations for avoidable courses and how to reduce them to a minimum were made in this analysis. Not at least this study was motivated by the lack of informations about obstetrical complications and the eventual consequences in literature. The only prophylaxis is the adequate support of the perineum and the sufficient episiotomy at the right moment. According to the operative and post operative treatment mentioned there could be achieved a good functional result in all cases. The stationary treatment has been reduced by these measures from 19,0 to 10,5 days.