OBJECTIVE: To quantify the association of pubic symphysis separation with mode of delivery and follow the resolution of this physiologic separation in the postpartum period. METHODS: Prospective observational cohort study that recruited two cohorts of primiparous women: those undergoing vaginal and cesarean delivery (45 and 46 patients, respectively). Chart review collected intrapartum factors. Patients were followed with serial anterior-posterior radiographs within 48 hours of delivery and at 6, 12, and 24 weeks postpartum, to evaluate the extent of pubic symphysis separation. Differences between the two cohorts in intrapartum factors were assesses as was pubic symphysis separation at each time point. RESULTS: Mean age of women was 25.8 (SD 5.1) years, and 56% were White. Mean birth weight was 3.5 (SD 0.52) kg. Mean immediate postpartum pubic symphysis separation was 7.6 (SD 2.2) mm and did not differ between groups, at 7.18 mm for vaginal delivery versus 8.04 mm for cesarean delivery (CD; P = 0.08). Pubic symphysis separation was not significantly different for CD with and without labour. Black race and obesity were associated with increased pubic symphysis separation. No intrapartum events were related to extent of separation. Normalization of pregnancy pubic symphysis separation to 4-5 mm occurred by 6 weeks postpartum. Separation of >10mm and <15mm occurred in 10 of the 91 women and occurred after vaginal and cesarean delivery. The widest pubic symphysis separation was observed in 3 patients after vaginal delivery. CONCLUSION: Physiological pubic symphysis separation occursduring pregnancy and regresses postpartum with minimal effects from labour and delivery. Cesarean deliverydoes not prevent physiological pubic symphysis separation.