Severity and impact of accidental bowel leakage two decades after no, one, or two sphincter injuries

BACKGROUND: Information about the long-term severity and sub-jective impact of anal incontinence in women after 1 or 2 consecutive obstetrical anal sphincter injuries is still scarce and contradictory. OBJECTIVE: This study aimed to describe the severity and impact of anal incontinence among women with 2 previous deliveries 2 decades after birth and to analyze the relative effect of 1 vs 2 obstetrical anal sphincter injuries in comparison with no obstetrical anal sphincter injuries and the possible influence of obstetrical anal sphincter injury on other pelvic floor disorders.STUDY DESIGN: We linked prospectively registered data in the Swedish Medical Birth Register with information from a postal and web-based questionnaire in 2015. Statistics Sweden identified women with 2 vaginal births from 1992 to 1998, and a simple random sample of 11,000 women was drawn from a source cohort of 64,687 women. To achieve equal-sized groups of women with 1 or 2 obstetrical anal sphincter injuries, the latter group was oversampled from 1987 to 2000. The final study cohorts consisted of 6760 women with no obstetrical anal sphincter injury, 357 women with 1 injury, and 324 women with 2 obstetrical anal sphincter injuries. Third-and fourth-degree perineal tears were grouped together for analysis. Anal incontinence was defined as either fecal or isolated gas incontinence, and fecal incontinence was defined as invol-untary leakage of solid or liquid stool with or without concomitant gas. Frequencies of leakage of stool and gas were dichotomized into low fre-quency (less than once a month) and high frequency (several times a month or more often). Pairwise comparisons were analyzed using Fisher exact tests, Mantel-Haenszel statistics, and the Mann-Whitney U test. Trends were analyzed using Mantel-Haenszel statistics and the Spearman rank correlation test. Logistic regression models were used to obtain the age-and body-mass-index-adjusted odds ratios for outcomes. Statistical significance was set at P<.05.RESULTS: The response rate was 65.5% in the randomly selected cohort and 70.1% among women with 2 obstetrical anal sphincter injuries. Bothersome fecal incontinence occurred in 3.3% (212/6458) of women without obstetrical anal sphincter injury, in 10.4% (36/345) (adjusted odds ratio, 3.25; 95% confidence interval, 2.23-4.73) of those with 1 injury, and in 16.5% (52/315) (adjusted odds ratio, 5.16; 95% confi-dence interval, 3.69-7.22) of those with 2 obstetrical anal sphincter injuries (trend P<.0001). Fecal incontinence was perceived as bother-some in 28.2% (212/753) of women without an obstetrical anal sphincter injury compared with in 43.9% (36/82) and 46.0% (52/113) of those with 1 or 2 obstetrical anal sphincter injuries (trend P<.0001). Leakage of liquid stool occurred in 10.8% (724/6717) of those without injury, in 21.7% (77/355) of women with 1 injury, and 34.9% (113/324) of women with 2 obstetrical anal sphincter injuries (trend P<.0001). Incontinence affecting daily life was reported by 8.6% (577/6672) of women without injury and by 19.7% (69/351) and 29.6% (96/324) of women with 1 and 2 sphincter injuries, respectively (trend P<.0001). The mean Jorge-Wexner score was 2.44, 3.26, and 3.88 for women with no, 1, or 2 sphincter injuries (trend P<.0001). Among women with a Jorge-Wexner score of 6, >50% had bothersome anal incontinence. The adjusted odds ratio for the overall effect of 1 vs 2 obstetrical anal sphincter injuries on measures of anal incontinence was 2.19 (95% confidence interval, 1.68-2.85) and 3.91 (95% confidence interval, 3.06-5. 00), respectively, when compared with no obstetrical anal sphincter injury (both P<.0001). Having 1 or 2 obstetrical anal sphincter injuries had no significant effect on other pelvic floor disorders or on lower urinary tract symptoms (P=.73 and P=.69).CONCLUSION: A consistent additive effect of 1 or 2 sphincter injuries on the severity and impact of anal incontinence was observed in women 2 decades after 2 vaginal births. This information is important for healthcare economics, clinical practice, and policy.