Obstetric Factors Associated with Pelvic Floor Disorders and Surgery 30 Years After Childbirth: A Prospective Cohort Study.

INTRODUCTION AND HYPOTHESIS: We aimed to compare symptoms of pelvic floor disorders (PFDs) and surgery risk by mode of delivery 30 years after first childbirth and assess symptom changes over time. We also examined associations between PFDs and pelvic floor muscle injuries. METHODS: Prospective cohort study in 2024 of women with first childbirth at Trondheim University Hospital, Norway in 1990-97. They responded to the pelvic floor distress inventory (PFDI-20) in 2013 and 2024. Ultrasound assessed pelvic floor muscle trauma in 2013-14. Outcomes included symptoms and surgery for PFDs and hysterectomy. RESULTS: Sixty percent of women (965/1606) responded 30.6 years after childbirth, with mean age 58.2 years; 140 (14.5%) had cesarean delivery, 414 (42.9%) normal vaginal delivery, 217 (22.5%) forceps, and 179 (18.5%) vacuum delivery. Cesarean delivery had lower mean PFDI-20 scores than normal vaginal delivery (28.9 vs 38.6), and no women in the cesarean group had PFD surgery. Forceps increased the risk for PFD surgery or hysterectomy (aOR 1.59 vs normal delivery; 1.68 vs vacuum). PFDI-20 score increased from 24.5 in 2013 to 37.9 in 2024, similarly for all delivery groups. Anal sphincter defects were associated with higher colorectal-anal and prolapse symptom scores and prolapse surgery (aOR 6.6), and levator ani injury with higher prolapse symptom scores and prolapse surgery (aOR 15.0). CONCLUSIONS: Thirty years after first childbirth, cesarean delivery was associated with lower symptom scores and no PFD surgery. Symptoms increased over time for all delivery methods. Forceps delivery increased surgery risk by 60% compared to normal vaginal and vacuum delivery, likely mediated by pelvic floor muscle injuries.