Estimating the prevalence of specific pelvic floor disorders, their associated severity and consequences for daily life is important information for health care planning. A recent study reported on the prevalence of fecal incontinence (FI) in women with no (12%), one (24%), or two (36%) obstetrical anal sphincter injuries (OASIs) [1]. In the present study we assessed the severity and subjective impact of FI and hypothesized that the severity and subjective impact of FI increased in women with no, one or two OASIs.

This is a register-based study initiated in 2015 in women with two deliveries. The Swedish National Board of Health and Welfare was requested to identify the potential study population from the Swedish Medical Birth Register (MBR), resulting in 64,687 non-pregnant 2-para women with singleton vaginal births between 1992 to 1998 and no further births. A sample of 11,000 women was randomly selected by Statistics Sweden and invited to participate in the study by returning a postal or a web questionnaire. The questionnaire was returned by 7145 women; 6760 women had no OASI, 357 had one OASI (253 at the first delivery only, and 104 at the second delivery), and 28 had OASI at both deliveries. To achieve equal-sized groups of women with one and two OASIs, the latter group was oversampled by extending the inclusion period to 1987-2000, resulting in 324 women with two OASIs. Given this size of study cohorts, an alfa level of 0.05, a power value of 80%, and using Fisher’s exact test for the analysis, the minimum significant difference in the prevalence of FI was 5% when comparing the control group with either of the two OASI cohorts and 11% when comparing the two OASI cohorts. Third- and fourth-degree OASIs were analyzed as one group. Diagnoses were retrieved from the MBR. OASI was identified by codes 664.2 and 664.3 in the International Classification of Diseases Ninth Revision (ICD-9) (1987-1996), and O70.2 and O70.3 in the Tenth Revision (ICD-10) and by the surgical code MBC33 (1997-2000).
The postal and web-based questionnaire included questions about current symptoms of solid and liquid stool and gas, urinary incontinence, and pelvic organ prolapse. The women were asked to report their current height and weight, menstrual status, hysterectomy, menopause, and hormone treatment. Information from the questionnaire was linked to obstetric details in the MBR. 
Continuous variables were presented as mean and standard deviations and categorical data as number and percentage. Pairwise comparisons were analyzed using Fisher’s exact test and the Mann-Whitney U-test for categorical and continuous variables. The results were presented as the mean difference for continuous variables and as the difference in percentages for categorical variables, 95% CI, and P value. The trend was analyzed using Mantel-Haenszel Chi-square statistics and Spearman´s rank correlation test. Logistic regression was used for analyzing the risk of bothersome FI or bothersome isolated gas incontinence (IGI). Results were presented as BMI and age-adjusted odds ratio (aOR) and 95% confidence interval (CI). Statistical significance was set at P < .05.

Bothersome FI increased 3- and 5-fold, from 3.3% in women without OASI, to 10.4% (aOR, 3.25; 95% CI, 2.23-4.73) in women with one OASI and 16.5 % (aOR, 5.16; 95% CI, 3.69-7.22) in women with two OASIs (Figure 1). The prevalence of IGI was about 40% in each group, but bothersome IGI was higher after one and two OASIs (Trend P = 0.0024). 28.2% of women without OASI perceived their FI as bothersome, compared to 43.9% and 46.0% in women with one or two OASIs (Trend P < .0001). The frequency of leakage of solid and liquid stool and IGI increased in women with one or two OASIs compared with those without (Trend all P<.0001). For example, the frequency of any leakage of liquid stool was 10.8% in women with no OASI, 21.7% in women with one, and 34.9% in women with two OASIs (Trend P < .0001). The use of pads was higher in the one and two OASIs groups compared with no OASI, from 2.3% in women without OASI to 7.1% and 8.4% in those with one and two OASIs (Trend P < .0001) (Figure 1). The effect on daily life was reported by 8.6% of women without OASI and 19.7% and 29.6% in women with one and two OASI (Trend P < .0001) (Figure 1). The mean Jorge-Wexner score increased from 2.44 to 3.26, and 3.88 in women with no, one, and two OASIs (Trend P < .0001). In women with a Jorge-Wexner score of six, more than 50% had bothersome anal incontinence (AI), and in those with a score of 9, almost 80% had bothersome AI (Figure 2). Few women had received treatment for bowel leakage, there were however significantly more women with one and two OASIs (3.4% and 4.1%) compared with women without OASI (1.3%) (Trend P < .0001) (Figure 1).

All components of the severity of anal incontinence – frequency of leakage, its mental impact (bother), coping strategies (use of pads), and the effect on daily life – all increased consistently in women with no, one or two OASIs.

The cumulative long-term risk of anal incontinence associated with sphincter injuries should be acknowledged by obstetricians and midwives and should be communicated to women as part of the antenatal consultation.

Nilsson IEK, Åkervall S, Molin M, Milsom I, Gyhagen M. Symptoms of fecal incontinence two decades after no, one, or two obstetrical anal sphincter injuries. Am J Obstet Gynecol. 2021;224:276.e1-276.e23. doi: 10.1016/j.ajog.2020.08.051.

Continence 2S2 (2022) 100376
DOI: 10.1016/j.cont.2022.100376