The impact of mode of subsequent birth after obstetric anal sphincter injury on bowel function and related quality of life: a cohort study

Introduction and hypothesis The objective was to assess the impact of mode of subsequent birth on bowel function and related quality of life (QoL) in pregnant women with previous obstetric anal sphincter injury (OASI). Methods A prospective cohort study, designed, undertaken and reported using the Strengthening the Reporting of Observational Studies in Epidemiology statement and checklist. All pregnant women with previous OASI recruited at a specialist antenatal OASI clinic in a tertiary hospital to discuss mode of subsequent birth, between 1 January 2014 and 31 October 2015. Women are counselled in line with local guidelines based on Royal College of Obstetricians and Gynaecologists Green-top recommendations. In addition to routine endoanal ultrasound scan (EAUS), women recruited to the study were asked to complete the validated Manchester Health Questionnaire (MHQ) at both 34 weeks’ gestation and 6 months postnatally. Results Of the 175 study participants, 125 (71.4%) completed follow-up at 6 months. There was no significant change in frequency of bowel symptoms or QoL domain scores in women who had a subsequent vaginal birth compared with caesarean section. Multivariate analysis showed the odds of having poor “incontinence impact” (OR 2.91, 95% CI 1.03–8.21) and “physical limitations” (OR 4.56, 95% CI 1.02–20.45) were significantly higher for women who had a subsequent caesarean section. Conclusions For women with previous OASI, a subsequent vaginal birth is suitable for those with no bowel symptoms and normal EAUS and caesarean section is reasonable for women who do not have normal bowel function and/or normal EAUS findings; however, for some of these women bowel symptoms and QoL may be worsened.