Age‐related long‐term effects of vaginal delivery, pregnancy, and sphincter injury on anal continence: A matched cohort study

Abstract Introduction It is still poorly understood to what extent various obstetric and non‐obstetric factors contribute to anal incontinence in women from a lifetime perspective. This study aimed to assess the contribution of pregnancy, delivery mode, obstetric anal sphincter injury (OASI), and age on anal incontinence in women aged 40–64 years. Material and Methods Data from the Swedish Medical Birth Register and the Total Population Register were linked to responses to an anal incontinence questionnaire collected in 2014 and 2015. The study included 13 480 women, 20 years from first birth, with BMI data: 4192 nulliparas, 2411 with two cesarean deliveries, and 6877 with two vaginal deliveries. Women were matched by exact age and BMI (±3 units), yielding three cohorts of 1961 women each. A subgroup analysis compared vaginally delivered women without OASI to those with one or two OASIs. Results The prevalence of fecal incontinence was highest in women with 2 vaginal deliveries (14.2%) and lowest in those with 2 cesarean deliveries (10.2%, p < 0.001). Fecal incontinence was significantly higher in nulliparous women (12.9%) compared with the cesarean group ( p < 0.01). Both bothersome fecal ( p = 0.001) and anal ( p < 0.001) incontinence were more common following vaginal delivery compared to cesarean delivery. Among women with 2 vaginal deliveries, the prevalence of fecal incontinence nearly doubled in those with OASI compared to those without (23.3% vs. 13.7%, p < 0.01). Women with OASI reported a greater symptom burden, demonstrated by a higher Jorge‐Wexner score (2.38 vs. 1.42, p < 0.001), increased use of protective products (7.8% vs. 3.0%, p = 0.025), and a higher reported impact on daily lifestyle (20.7% vs. 10.1%, p = 0.002). Only women with two vaginal deliveries showed a significant age‐related increase in fecal incontinence. Conclusions Long‐term fecal incontinence was more common and severe after vaginal delivery, particularly with OASI. An age‐related effect on fecal incontinence was observed only among vaginal deliveries. Even with complete prevention of OASI through perineal protection, a significant age‐related increase in fecal incontinence between 40 and 62 years would remain, arising solely from the effect of vaginal delivery. Preventing OASI remains an important obstetric target to reduce fecal incontinence later in life.