Antibiotic use and wound complications among people with obstetric anal sphincter injuries

Abstract

To examine rates of antibiotic administration and wound complications among people with obstetric anal sphincter injuries (OASIS) at time of delivery. Retrospective cohort analysis of all people delivering a liveborn singleton infant vaginally and experiencing OASIS at 4 hospitals within one healthcare system between July 2016-2021. People with OASIS were identified based on the delivery report entered into the electronic medical record (EMR) by the providers at the time of delivery. Antibiotic administration on the day of delivery was obtained from the EMR. Wound complications occurring within 4 months of delivery were identified from ICD10 codes for infection or disruption of a perineal or obstetric laceration. Logistic regression was used to identify factors associated with the administration of antibiotics and with postpartum wound complications. There were 1,550 cases of OASIS; antibiotics were administered to 855 (55.2%). Antibiotic regimens varied widely; 7.5% received a second or third generation cephalosporin. Factors associated with any antibiotic administration in univariate analysis are listed in Table 1. In an adjusted model controlling for race, delivery BMI, length of second stage, operative delivery, and 4th degree laceration, only operative vaginal delivery (OR 1.59, 95% CI 1.31, 1.93) and 4th degree laceration (OR 2.64, 95% CI 2.21, 3.17) remained significant. There were 46 (3.0%) wound complications. There was no difference in the rate of wound complications among women who did and did not receive antibiotics on the day of delivery (2.8 vs 3.2%, p=0.68), including when controlling for BMI, race, and second stage length. Nearly half of this cohort with OASIS did not receive any antibiotics on the day of delivery. Despite this, wound complications were rare and did not vary by antibiotic administration. Further research evaluating the optimal timing of antibiotic administration as well as the most effective antibiotic regimen in the setting of OASIS is needed.