Complications Following Obstetric Anal Sphincter Injury Up to One Year Postpartum

INTRODUCTION: Obstetric anal sphincter injury (OASI) can cause complications such as fecal incontinence, pain, and fistula, amongst other issues. Given that OASI is uncommon, outcomes are difficult to study, and a gap in knowledge exists. OBJECTIVE: This study's main objective is to compare the incidence of postpartum complications within one year in women with and without OASI. METHODS: This retrospective cohort study utilized a maternal-infant-linked database of births to Florida-resident women from 2006 to 2019. Birth certificates were linked to inpatient, emergency department, and outpatient surgical encounters. Women with a vaginal delivery were included in our study. Women with OASI were identified using a combination of birth certificate indicators and ICD-9/10 diagnosis codes. We used diagnoses and procedure codes documented during encounters up to one year postpartum to identify complications. We then compared the incidence of the following diagnoses between women with and without OASI: genitourinary infections, bleeding, fistula, gastrointestinal complications, wound complications, urinary retention, urinary incontinence, pelvic organ prolapse, genital pain disorders, chronic pain disorders, chronic pain syndrome, acute genital pain, anal/rectal pain, and fecal incontinence. Procedures included were wound infection procedures, blood transfusion, fistula repair, gastrointestinal procedures, wound repairs, and urinary incontinence procedures. The statistical significance of differences between women with and without OASI were assessed with a Fisher’s exact test. RESULTS: There were 2,694,441 live births identified from 2006 to 2019. 1,125,974 women had a cesarean section and were excluded. There were 1,527,599 women with a vaginal delivery who were included, and 40,868 of those women had an OASI. There was a 2.6% incidence of OASI in vaginal live births in this cohort. Most women were White, non-Hispanic, and the majority of women with OASI were nulliparous (80.8%). 5,843 women (14.3%) with OASI had an operative delivery compared to 46,689 (3%) without OASI (Table 1). Women with OASI had a significantly increased risk of fistula, gastrointestinal complications, wound complications, urinary retention, acute genital pain, and fecal incontinence compared to women without OASI. Women without OASI had a significantly increased risk for genitourinary infections and chronic pain syndromes compared to women with OASI (Table 2). Women with OASI had a significantly increased risk of having a fistula and wound repair (Table 2). CONCLUSIONS: Compared to women without OASI, women with OASI are more likely to experience wound, bowel, and bladder complications and have more acute pain in the first year postpartum.