Association between mode of delivery and pelvic floor dysfunction.

BACKGROUND Normal vaginal delivery can cause significant strain on the pelvic floor. We present a review of the current knowledge on vaginal delivery as a risk factor for urinary incontinence and pelvic organ prolapse compared to caesarean section. MATERIAL AND METHOD We conducted a literature search in PubMed with an emphasis on systematic review articles and meta-analyses. The search was completed in January 2014. We also included articles from our own literature archives. RESULTS Compared to vaginal delivery, caesarean section appears to protect against urinary incontinence, but the effect decreases after patients reach their fifties. The risk of pelvic organ prolapse increases (dose-response effect) with the number of vaginal deliveries compared to caesarean sections. There are few reliable studies on the association between mode of delivery and anal incontinence, but meta-analyses may indicate that caesarean section does not offer protection after the postpartum period. Women with previous anal sphincter rupture during vaginal delivery are a sub-group with an elevated risk of anal incontinence. The degree of severity of pelvic floor dysfunction is frequently unreported in the literature. INTERPRETATION The prevalence of urinary incontinence and pelvic organ prolapse is lower in women who have only delivered by caesarean section than in those who have delivered vaginally. For urinary incontinence this difference appears to level out with increasing age. There is no basis for identifying sub-groups with a high risk of pelvic floor injury, with the exception of women who have previously had an anal sphincter rupture. Caesarean section will have a limited primary preventive effect on pelvic floor dysfunction at a population level.