Effect of Universal Antibiotic Prophylaxis on Prevalence of Surgical Site Infection After Cesarean Section

<b>Background/Objectives</b>: Cesarean section (CS) is among the most common surgical procedures worldwide and is associated with a markedly increased risk of postpartum infection, including surgical site infection (SSI). International guidelines recommend routine prophylaxis for all CSs, but in Slovenia, it has traditionally been reserved for high-risk procedures, with limited SSI surveillance data. The aim of this study was to determine the incidence of SSI within 30 days after CS and to evaluate the impact of universal prophylaxis implemented in a regional secondary care teaching hospital. <b>Methods</b>: We conducted a retrospective observational cohort study including all CS performed during 2023 (risk-based-only prophylaxis) and 2024 (universal prophylaxis) at Izola General Hospital, Slovenia. SSI was defined according to ECDC criteria and identified from inpatient and outpatient records up to 30 days postoperatively. Logistic regression was used to assess associations between prophylaxis, clinical variables, and SSI. <b>Results</b>: Among 1055 deliveries (208 CS; 99 in 2023, 109 in 2024), the rate of antimicrobial prophylaxis increased from 58.6% to 89.0% (<i>p</i> < 0.001). The overall 30-day SSI incidence was 7.2%, with no significant difference between the pre- and post-implementation periods (8.1% vs. 6.4%, <i>p</i> = 0.644). Most infections (86.7%) were diagnosed after discharge and were superficial incisional SSI (60%). In multivariable analysis, prophylaxis was independently protective (adjusted OR 0.11; 95% CI 0.02-0.58; <i>p</i> = 0.009), while prelabor rupture of membranes (PROM) and higher maternal weight significantly increased SSI risk. <b>Conclusions</b>: Antibiotic prophylaxis was independently associated with a reduced risk of SSI following SC; however, the absolute infection rate did not decline significantly and remained moderate after implementation. PROM and higher maternal weight were additional independent risk factors. These findings support universal prophylaxis with optimization for high-risk women and ongoing hospital and national surveillance to improve CS safety.