A randomised trial comparing preoperative administration of single-dose kefazolin to kefazolin plus metronidazole as prophylactic antibiotics at caesarean section.

Background: Caesarean section is a life-saving procedure which is associated with high rates of maternal and neonatal complications. It has been estimated that globally, 29.7 million births occur by caesarean section annually. The risk of postpartum infection is estimated to be five to ten times higher compared with normal vaginal delivery. Pregnancy-related sepsis was listed as a top-six cause of maternal mortality in the South African Saving Mothers report between 2017 and 2019. Multiple trials have been conducted in an attempt to optimise administration of prophylactic antibiotics in an effort to reduce postpartum infection and maternal sepsis, and current practice guidelines suggest that there is sufficient evidence that extended-spectrum antibiotics, in combination with kefazolin, result in reduction of postpartum infections.

Objectives: To investigate the effect of perioperative administration of kefazolin alone compared with kefazolin plus metronidazole on postpartum infection in women undergoing caesarean section at Kalafong Provincial Tertiary Hospital, Pretoria, South Africa.

Method: All patients undergoing emergency or elective caesarean section were randomised and then sequentially numbered in opaque sealed envelopes, which were placed in the caesarean section operating theatre. The intervention group received kefazolin and a sealed envelope with metronidazole. The control group received kefazolin and a sealed envelope with normal saline.

Results: A total of 57/1 010 patients (5.64%) had surgical site infections, of which 27 (5.33%) were in the control group, and 30 (5.96%) were in the intervention group (p=0.66). Two patients in each arm (0.40% in the intervention arm and 0.39% in the control arm) underwent laparotomy procedures, while three women (0.60%) in the intervention arm and four women (0.79%) in the control arm underwent hysterectomy procedures. There were no statistically significant differences in all the measured secondary outcomes between the two groups.

Conclusion: The overall sepsis rate in this study was 5.64%. Postpartum infection is multifactorial and there are multiple factors that can be addressed in strengthening the sepsis care bundle. We do not recommend the addition of metronidazole to kefazolin as prophylaxis at caesarean section.