Cefazolin versus cefazolin plus metronidazole for antibiotic prophylaxis at cesarean section.

BACKGROUND Although prophylactic antibiotic medications have been shown to reduce the incidence of postoperative infectious morbidity after cesarean delivery, the most effective regimens have not been established. The purpose of this investigation was to compare the efficacy and costs of prophylaxis with cefazolin alone with cefazolin plus metronidazole. METHODS Women undergoing cesarean delivery were randomized to prophylaxis with 2 g cefazolin (n = 81) or 1 g cefazolin plus 500 mg metronidazole (n = 79). Postoperative infectious morbidity and the duration of hospitalization in the two groups were compared. RESULTS Thirty-seven (23%) of 160 patients developed endomyometritis. There was a significant reduction in the number of postoperative infections (14 versus 32%) and hospital days (3.12 versus 4.46) with cefazolin and metronidazole prophylaxis (P = 0.0064 versus P = 0.014) compared with cefazolin alone. The estimated antibiotic prophylaxis cost per person was less with cefazolin and metronidazole than with cefazolin alone (9.12 dollars versus 26.73 dollars). CONCLUSION Antibiotic prophylaxis with metronidazole and cefazolin results in fewer postoperative infections, decreased duration of hospitalization, and lower medication cost than cefazolin alone.