Mode of delivery following obstetric anal sphincter injury: a 7-year retrospective review and follow-up cohort survey.

Abstract

Limited evidence exists regarding long-term outcomes following birth after prior obstetric anal sphincter injury (OASI). This article set out to describe outcomes following birth after OASI by reviewing the grades of tear, endoanal ultrasound (EAUS) findings, subsequent delivery outcomes and long-term symptoms. This study was conducted in two parts. The first involved a retrospective review of all OASI at a tertiary hospital in Australia over 7 years (2013-2019 inclusive) where the patient underwent a subsequent delivery. Following this, a retrospective cohort survey of this group was performed. There were 27,284 vaginal births and 828 OASIs (3.03%); 247 (29.8%) had at least one subsequent birth by January 2021. Vaginal delivery occurred in 68%; recurrence of OASI was 5.4%. There were 90 responses (36.4%) to the follow-up survey. EAUS had been performed in 87.5%; none demonstrated a defect. Vaginal birth was the preferred mode for 77.8%; this occurred in 64%. The majority had high levels of satisfaction, this related to communication rather than the mode of delivery itself. Ongoing faecal or flatal incontinence was reported by 12%. There was no statistically significant difference in St Mark's incontinence scores between modes of birth. In our unit most women who sustain OASI will have a subsequent vaginal delivery in future pregnancies. The majority remain asymptomatic at long-term follow-up with no statistically significant difference in incontinence scores regardless of mode of delivery. The rate of recurrent OASI was 5.4%.