Surgical site infections are a significant cause of morbidity following cesarean deliveries. Preoperative prophylaxis with cephalosporins is the standard of care; however, obesity remains an independent risk factor. Effective preventive measures are essential to improve maternal health and reduce costs. This study aimed to evaluate the efficacy of oral cephalexin and metronidazole prophylaxis in the postoperative period of cesarean sections.

A systematic search was conducted in PubMed, Embase, and Cochrane databases for randomized clinical trials evaluating the efficacy of oral cephalexin and metronidazole for preventing surgical site infection, incision dehiscence, fever, endometritis, and cellulitis after cesarean section. Statistical analyses were performed using R software (version 4.5.0), with risk ratio as the effect measure. Results were expressed as geometric means and geometric mean ratios, applying a random-effects model and a 5% significance level. Heterogeneity was assessed using the I² statistic. Sensitivity analyses were performed when data were available.

Three randomized controlled trials were included, totaling 1,144 patients—572 in the oral antibiotic prophylaxis group (cephalexin plus metronidazole) and 572 in the control group. The mean age of participants was 27 years, and the mean BMI was 37 kg/m². A significant reduction was observed in the incidence of cellulitis (RR = 0.41; 95% CI 0.25–0.67; p < 0.001; I² = 0%) and surgical site infection (RR = 0.39; 95% CI 0.27–0.58; p < 0.001; I² = 0%) in the intervention group. No statistically significant differences were found between groups for endometritis (RR = 0.37; 95% CI 0.11–1.21; p = 0.102; I² = 0%), fever (RR = 0.68; 95% CI 0.36–1.30; p = 0.247; I² = 46.4%), or wound separation (RR = 0.47; 95% CI 0.18–1.20; p = 0.113; I² = 55.3%).

This meta-analysis confirms that postoperative oral antibiotic prophylaxis with cephalexin and metronidazole is effective in reducing surgical site infections and cellulitis after cesarean delivery. These findings support its use as an adjuvant strategy for preventing infectious complications in obstetric settings, particularly among high-risk populations such as obese patients.