Objective: To assess whether antibiotic administration changes the rate of materno-fetal infectious morbidity in premature rupture of membranes occurring later than 35 weeks of gestation.
Methods: A prospective, randomized and multicentric study in the Perinatology Units of eleven hospitals in Spain. Women were randomized to either antibiotic administration or control group. All were induced, if labor had not started spontaneously after 12 hours of ruptured membranes. Main outcome measures were maternal infection (chorioamnionitis and endometritis) and neonatal infectious morbidity (neonatal sepsis, meningitis and bronchopneumonia).
Results: Seven hundred and thirty-three patients were enrolled in the study, 371 in the antibiotics group and 362 in the control group. The incidence of chorioamnionitis and puerperal endometritis were reduced but the differences are statistically nonsignificant. However, the incidence of neonatal sepsis was significantly lower in newborns to mothers who had received antibiotics, 1 vs. 7 cases (Fisher's exact test, p<0.007).
Conclusion: The study strongly suggests that prophylactic use of antibiotics in premature rupture of membranes occurring at 36 or more weeks of gestation reduces the risk of neonatal sepsis and probably maternal endometritis.