Risk Factors for Wound Complications After Obstetric Anal Sphincter Injury

Wound complications after obstetric anal sphincter injury (OASI) can amplify morbidity and affect quality of life.

The objective of this study was to evaluate for characteristics associated with wound complications after OASI.

This was a retrospective cohort study of patients with an OASI who were evaluated in a postpartum pelvic floor healing clinic between November 1, 2020, and May 16, 2023. Our primary outcome was to identify factors associated with wound complications (wound infection or breakdown, antibiotic treatment, or surgical intervention). We hypothesized that operative vaginal delivery would be associated with wound complications and that peripartum antibiotics would be protective. Statistical analyses included t tests, chi-square test, Fisher exact test, and multivariable logistic regression.

Of 332 patients with an OASI, 74 (22.3%) experienced a wound complication. There were 31 (9.3%) wound infections and 62 (18.7%) wound breakdowns; 50 (15.1%) patients received additional antibiotics, and 20 (6.0%) underwent additional surgical intervention. On univariate analysis, those with wound complications were older (31.9 vs 30.6 years, P = 0.01) and more likely to have had an episiotomy (23.0% vs 12.5%, P = 0.03). On multivariable logistic regression, older maternal age was associated with wound complication (odds ratio, 1.1, 95% CI, 1.01-1.13, P = 0.03), and peripartum antibiotics were associated with decreased odds of wound complication (odds ratio, 0.57, 95% CI, 0.33-0.97, P = 0.04). Patients with wound complications were more likely to undergo in-office procedures ( P < 0.001) and report postpartum pain ( P < 0.001), urinary incontinence ( P = 0.02), fecal urgency ( P = 0.02), and other symptoms ( P = 0.04).

Older maternal age was associated with wound complications after OASI, while peripartum antibiotics were protective. Patients with wound complications were more likely to report symptoms of pelvic floor disorders.