Antibiotic administration and wound complications after obstetric anal sphincter injuries.

Background: Obstetric anal sphincter injuries are associated with both short-term and long-term maternal morbidity. Antibiotic administration has been shown to decrease wound complications after obstetric anal sphincter injuries. However, the rate of antibiotic administration in a contemporary obstetrical population is not known.
Objective: This study aimed to describe the rate of antibiotic administration for obstetric anal sphincter injuries, to characterize factors associated with antibiotic administration on the day of delivery among women with obstetric anal sphincter injuries, and to determine if there was an association between antibiotic administration and reduced wound complications.
Study Design: This was a retrospective cohort study of women with a singleton vaginal birth complicated by obstetric anal sphincter injuries between 2016 and 2021 in a single healthcare system. Information about any antibiotic administration on the day of delivery was collected. Information on wound complications (determined by International Classification of Disease, 10th Revision, codes) that occurred within the first 6 months postpartum were available for patients who delivered at tertiary-care centers. Multivariable logistic regression analysis was used to identify factors associated with antibiotic administration and the association between antibiotics and wound complications.
Results: During the study period, 1550 women met the inclusion criteria of whom 855 (55.2%) received antibiotics. Antibiotic administration was higher at tertiary-care hospitals than at community-based hospitals (68.7 vs 26.8%; P<.001). In the adjusted analysis, antibiotic administration was higher among women with a fourth-degree laceration (adjusted odds ratio, 2.72; 95% confidence interval, 1.69-4.37) and lower among women of Asian or Pacific Islander heritage (adjusted odds ratio, 0.88; 95% confidence interval, 0.80-0.97). At tertiary-care hospitals, 43 women (4.1%) had a wound complication, and more than 80% of those presented within the first 2 weeks postpartum. Antibiotic use was associated with reduced rates of wound complications (adjusted odds ratio, 0.34; 95% confidence interval, 0.13-0.91). All patients received a regimen with gram-positive bacterial coverage; there was no association between type of antibiotic regimen administered and wound complications.
Conclusion: Any antibiotic administration on the day of delivery was associated with a decreased rate of wound complications after obstetric anal sphincter injuries. However, only about half of the women with obstetric anal sphincter injuries received antibiotics. Optimizing antibiotic administration may help to reduce the risk of complications in this population.
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