Cesarean delivery and postnatal infection
For one study, researchers sought to determine the relationship between the timing of adjuvant azithromycin administration for prophylaxis during unplanned caesarean section and maternal infection and neonatal morbidity. A secondary analysis of a randomized trial of additional azithromycin prophylaxis was performed in patients with a singleton pregnancy who had an unplanned caesarean section. The time of study drug initiation (after skin incision or 0-30 minutes, more than 30-60 minutes or more than 60 minutes before skin incision) was the primary exposure. Endometritis, wound infection, and other maternal infections occurring up to 6 weeks after cesarean delivery were the primary outcomes. Composite neonatal morbidity, neonatal intensive care unit hospitalization for more than 72 hours, and neonatal sepsis were secondary outcomes. The relationship between azithromycin and outcome was examined in each antibiotic therapy timing group and provided as 95% relative risks (RRs) (CI). To investigate association changes by timing of antibiotic therapy, a Breslow-Day homogeneity test was used.
Antibiotics were started after skin incision (median 3 minutes, range 0-229 minutes) in 269 (13.4%), 0-30 minutes before skin incision in 1378 (68.5%) and more than 30 to 60 minutes before skin incision in 270 (13.4%) and more than 60 minutes before skin incision (median 85 minutes, range 61 to 218 minutes) in 96 (of 2013 participants) ( 4.8%). The RRs (95% CI) of the infectious composite outcome for azithromycin were significantly lower in the groups that started azithromycin after skin incision or within one hour before skin incision (after skin incision: RR 0, 31, 95% CI 0.13-0.76, 0-30 minutes before: RR 0.62, 95% CI 0.44-0.89, more than 30-60 minutes before: 0.31, CI 95 % 0.13–0.66). Patients who received azithromycin more than 60 minutes before skin incision had no increased risk ( RR 0.59, 95% CI 0.10–3.36). When endometritis and wound infections were studied independently, the results were identical. In all time groups, there was no significant difference in neonatal outcomes between azithromycin and placebo. Adjunctive treatment with azithromycin up to 60 minutes before or 3 minutes after skin incision was linked to lower rates of maternal composite postoperative infection in unplanned caesarean sections.