In a prospective study, pelvic floor muscle strength was investigated pre- and post partum in 87 women with uncomplicated pregnancies. Those vaginally delivered were 71 primiparas, while 16 underwent an elective cesarean section. The objective was to evaluate the effect of the delivery procedure on the pelvic floor muscle strength with the aid of vaginal cones. In the group of women with vaginal delivery three subgroups were identified: episiotomy, spontaneous laceration and intact perineum. Pelvic floor muscle strength was weakest in the episiotomy subgroup, the difference in values between this subgroup and each of the other subgroups and the elective cesarean section group being significant. No significant difference was evident between the spontaneous lacerations and intact perineum subgroups.