Symptoms of fecal incontinence two decades after one and two obstetric anal sphincter injuries.

Abstract Background The long-term effects of one or two consecutive obstetric anal sphincter injuries on bowel continence are still inadequately investigated and published results remain contradictory. Objectives The aim was to present detailed descriptive measures of current bowel incontinence 20 years after the first birth in two-para women with and without sphincter injuries. Study design Birth register data were used prospectively and linked to information from a questionnaire survey about current symptoms. Women with two singleton vaginal births, 1992-1998, and no further births were retrieved and surveyed by the Swedish Medical Birth Register and by Statistics Sweden in 2015. A simple random sample of 11,000 women was drawn from a source cohort of 64,687 women. The additive effect was studied in all women with a repeat sphincter injury from 1987 to 2000. Postal and web-based questionnaires were used. The study population consisted of 6760 women with no, 357 with one, and 324 women with two sphincter injuries. We compared women with one and two consecutive sphincter injuries using women aged 40 to 60 years with two deliveries without sphincter injury as reference. Third- and fourth-degree perineal tears were presented as one group. Fecal incontinence was defined as current involuntary leakage of solid and/or liquid stool, with and without concomitant leakage of gas. For comparison between groups, Fisher’s exact test and the Mann–Whitney U test were used. The trend was analyzed with Mantel-Haenszel statistics. Logistic regression models obtained the estimated age-related probability of fecal incontinence components. Results The risk of sphincter injury at the first delivery was 3.9% and the risk of a repeat sphincter injury was 10.0% (OR 2.70, 95%CI 1.80;4.07). The overall prevalence of fecal incontinence in women without sphincter injuries was 11.7% doubling to 23.8% (OR 2.27, 95%CI 1.75; 2.94) in those with one sphincter injury, and more than tripled to 36.1% (OR 3.97, 95%CI 3.11; 5.07) after two sphincter injuries (Trend P Conclusions The risk of sustaining a repeat sphincter injury was almost tripled compared with the risk among nulliparous women. One and two sphincter injuries brought severe long-term consequences for bowel continence. Accidental leakage of stool and gas increased with each sphincter injury, and the effect was proportionally additive. After ∼52 years of age, the prevalence of fecal incontinence seemed to accelerate.