Objectives To assess if mode of delivery is associated with increased symptoms of anal incontinence following childbirth.
Design Systematic review of all relevant studies in English.
Data sources Medline, Embase, Cochrane Library, bibliographies of retrieved primary articles and consultation with experts.
Study selection and data extraction Data were extracted on study characteristics, quality and results. Exposure to risk factors was compared between women with and without anal incontinence. Categorical data in 2 × 2 contingency tables were used to generate odds ratios.
Results Eighteen studies met the inclusion criteria with 12 237 participants. Women having any type of vaginal delivery compared with a caesarean section have an increased risk of developing symptoms of solid, liquid or flatus anal incontinence. The risk varies with the mode of delivery ranging from a doubled risk with a forceps delivery (OR 2.01, 95% CI 1.47–2.74, P < 0.0001) to a third increased risk for a spontaneous vaginal delivery (OR 1.32, 95% CI 1.04–1.68, P = 0.02). Instrumental deliveries also resulted in more symptoms of anal incontinence when compared with spontaneous vaginal delivery (OR 1.47, 95% CI 1.22–1.78). This was statistically significant for forceps deliveries alone (OR 1.5, 95% CI 1.19–1.89, P = 0.0006) but not for ventouse deliveries (OR 1.31, 95% CI 0.97–1.77, P = 0.08). When symptoms of solid and liquid anal incontinence alone were assessed, these trends persisted but were no longer statistically significant.
Conclusion Symptoms of anal incontinence in the first year postpartum are associated with mode of delivery.