Adjunctive intravaginal metronidazole for the prevention of postcesarean endometritis: A randomized controlled trial

OBJECTIVE: To estimate the efficacy of preoperative administration of intra vaginal metronidazole for the prevention of postcesarean endometritis. METHODS: This double-masked, placebo-controlled randomized trial included p atients of at least 24 weeks' gestation undergoing cesarean deliveries for various indications. Patients were randomized to receive either 5 g of metr onidazole gel intravaginally or matching placebo before the initiation of t he cesarean. All patients underwent surgical cleansing of the abdomen, and most received prophylactic antibiotics after cord damping. Patients with ch orioamnionitis and/or suspected allergy to metronidazole were excluded. For a two-sided alpha of 0.05 and beta of 0.20 (80% power), 120 subjects were required in each group. The main outcome variable was the incidence of post cesarean endometritis. Secondary outcome variables included presence of feb rile morbidity, wound infection, clays on antibiotics, and length of postpa rtum hospitalization. Neonatal outcomes included birth weight, Apgar scores less than 7 at 5 minutes, umbilical arterial pH less than 7.16, admission and length of stay in the neonatal intensive care unit, and length of hospi tal stay. RESULTS: Of 112 patients receiving metronidazole, eight (7%) developed post cesarean endometritis, compared with 19 of 112 (17%) of those receiving pla cebo gel (relative risk 0.42, 95% confidence interval 0.19, 0.92). No signi ficant differences were noted between treatment groups with respect to the other outcome variables. CONCLUSION: The preoperative administration of 5 g of intravaginal metronid azole gel appears to reduce the incidence of postcesarean endometritis. (Ob stet Gynecol 2001;98:745-50. (C) 2001 by the American College of Obstetrici ans and Gynecologists).