815 Timing of diagnosis of endometritis and wound infection after unscheduled cesarean sections: contemporary data

Abstract

Data on timing of surgical site infection (SSI) after cesarean delivery (CD) is mostly from studies before the era of adjunctive azithromycin prophylaxis. Our objective was to evaluate the timing of SSI after unscheduled CD using contemporary data. This is a secondary analysis of a recent multicenter trial of adjunctive azithromycin vs. placebo for prophylaxis in women who underwent unscheduled CD (all received standard prophylaxis) (Tita AT et al. NEJM 2016). The primary outcome was a composite of any post-CD infections (predominantly endometritis or wound infections). Timing was categorized as post-operative day at diagnosis: 0-2, 3, 4, 5-7, 8-14, 15-21 and >21 days. The relative and cumulative frequencies of outcomes were computed for increasing time separately for endometritis and wound infection, and was further stratified by azithromycin vs. placebo. Among 2013 women at 14 centers, 181 (9%) had one or more infections: 90 wound infections, 100 endometritis and 9 other infections (15 had more than 1 infection). Women with infections were more likely to be Black, and have higher BMI compared to those with no infection. Endometritis was more common than wound infection within 4 days (85% vs 4.4%) and within 1 week (93% vs. 20%). Cumulatively, 87.8% of wound infections occurred within 3 weeks. The peak for endometritis was during the first 2 days (72%) vs. the peak for wound infections in days 8-14 (47.8%) (Fig. 1). Although fewer infections occurred in the azithromycin group, the overall pattern of timing was similar in both azithromycin and placebo groups (Table 1). These contemporary data in the era of adjunctive azithromycin prophylaxis indicate that the vast majority of endometritis cases occur within a few days after cesarean section- usually during inpatient hospital stay, whereas wound infections occur after the first week.View Large Image Figure ViewerDownload Hi-res image Download (PPT)