This study concerns clinical data of 142 women, who were subjected to functional evaluation of perineum during the last part of pregnancy. The 16 cases characterized by synergic activation, during the examination of perineal muscles ("perineal testing"), of antagonist muscles ("inverted control"), were examined taking into account data regarding evolution of labour and perineal outcome. "Inverted control" seems to influence, in this study, length of the second stage and frequency of operative deliveries whereas we can't confirm the importance of this disorder within pathogenesis of perineal obstetric complications.