Impact of Prior Cesarean Section on Surgical Site Infections, Microbiological patterns, and Surgical Outcomes: A Prospective Multicenter Cohort Study in South Ethiopia

Background Cesarean section (CS) is a widely performed lifesaving surgical procedure; however, it may also carry risks of maternal complications, especially with repeated exposure. Evidence from prospective studies in low-resource settings is limited. This study provides insights to guide interventions and implement maternal health policies for women undergoing repeat CS in low-resource settings like Ethiopia Objective To assess whether prior CS increases the risk of postoperative surgical site infections (SSI), alters microbiological profiles, and contributes to intra- and postoperative complications compared with first-time CS. Methods A multicenter prospective cohort study was conducted from January to December 2022 among 1,506 women undergoing CS at one primary, one general, and one university comprehensive specialized hospital. Participants were enrolled into two cohorts: 753 women with ≥ 1 prior CS (exposed) and 753 undergoing first-time CS (unexposed). All participants were followed for 30 days postoperatively. The primary outcome was SSI; secondary outcomes included SSI type, microbiology, and perioperative complications. Data were analyzed using SPSS v25 with Poisson regression and robust variance estimators; p-value ≤ 0.05 was considered statistically significant. Results Overall SSI incidence was 13.5% (95% CI: 11.9–15.4%). Repeat CS had higher SSI rates than primary CS (20.3% vs. 6.8%; RR = 2.98, 95% CI: 2.20–4.03; p < 0.001 ), particularly deep incisional SSIs (30.1% vs. 9.8%; RR = 3.07; p = 0.012 ). Gram-negative isolates predominated in repeat CS (83.8% vs. 68.6%; p = 0.027 ). Adjusted analyses confirmed repeat CS as a strong independent predictor of SSI (aRR = 2.94, 95% CI: 2.20–3.93). Risk was highest in the university comprehensive specialized hospital and emergency CS. Women with ≥ 3 prior CS had nearly fourfold higher SSI risk. Repeat CS was also associated with longer operative time, greater use of general anesthesia, higher transfusion and antibiotic use, and longer hospital stay (p < 0.05). Additional independent predictors of SSI included emergency CS, history of hospitalization and aqueous povidone-iodine (10%) skin preparation with (aRR = 1.76, 95% CI: 1.06–2.91), (aRR = 1.56, 95% CI: 1.18–2.10), and (aRR = 2.39, 95% CI: 1.45–3.94), respectively. Conclusion Repeat CS is associated with a threefold higher risk of SSI, more severe complications, and Gram-negative predominance. Risk-stratified interventions, optimized infection prevention, careful surgical planning, and antimicrobial stewardship are essential to improve outcomes