ABSTRACT: To compare the effectiveness of antibiotic prophylaxis before skin incision with that after umbilical cord clamping in elective caesarean delivery.We conducted a randomized open-label controlled trial with two parallel arms at three hospitals in western China. Participants meeting the inclusion criteria received antibiotics 30-60 minutes before skin incision while others received antibiotics after umbilical cords clamping. For the meta-analysis, studies were identified from the database of PUBMED, Cochrane Library and EMbase and assessed using the Cochrane risk of bias tool.Four hundred and ten patients were randomized to receive antibiotics before skin incision (n = 205) or after umbilical cords clamping (n = 205). There was no difference in the incidence of postpartum endometritis (RR = 0.34, 95% CI 0.04 to 3.24), wound infection (RR = 3.06, 95% CI 0.13 to 74.69) and total puerperal morbidity (RR = 1.02, 95% CI 0.47 to 2.22). No increase in the incidence of neonatal sepsis (RR = 0.34, 95% CI 0.04 to 3.24), septic workup (RR = 0.41, 95% CI 0.08 to 2.07), or intermediate NICU admission (RR = 0.73, 95% CI 0.24 to 2.26) was observed. The meta-analysis involving nine RCTs showed that no statistically significant difference was found in terms of the risk of postpartum endometritis (RR = 0.73, 95% CI 0.39, 1.36), wound infection (RR = 0.80, 95%CI 0.55, 1.17), or puerperal morbidity (RR = 0.89, 95% CI 0.70, 1.13). No increase in the incidence of neonatal sepsis (RR = 0.65, 95% CI 0.35 to 1.20), septic workup (RR = 0.88, 95% CI 0.50 to 1.54), or intermediate NICU admission (RR = 0.91, 95% CI 0.70 to 1.18) was observed.For elective caesarean delivery, the effects of antibiotic prophylaxis before skin incision and after umbilical cord clamping were equal. Both antibiotic prophylaxis before skin incision and that after umbilical cord clamping were recommended for elective caesarean delivery. The outcome of further studies should address both maternal and neonatal infectious morbidity as well as long-term neonatal follow up.Chinese Clinical Trial Registry ChiCTR-TRC-11001853.