Intrapartum antibiotics and risk factors for early onset sepsis

Objective To determine the independent risk factors for early onset neonatal sepsis (EONS) in a setting where the policy is to use intrapartum antibiotic prophylaxis (IAP) for known risk factors. Design Prospective cohort study. Setting Level III neonatal unit in a developing country. Patients Consecutive mother-infant dyads (gestation <= 34 weeks) with no major neonatal malformations. Interventions Thirteen putative maternal and neonatal risk factors and use of IAP were assessed. Neonates were followed until 72 h of life for signs of EONS. Blood cultures were drawn on clinical suspicion of EONS and/or prior to starting prophylactic antibiotics for high risk asymptomatic neonates. Main outcome Culture-proven EONS (onset at < 72 h). Results 601 mother-infant dyads were enrolled (mean (SD) gestation=31.8 (2) weeks; mean (SD) birth weight 1559.4 (452) g). The best fitted multivariable logistic regression model had six independent risk factors (adjusted OR (95% CI)): vaginal examinations >= 3 (9.5 (3 to 31)), clinical chorioamnionitis (8.8 (2 to 43)), birth weight < 1500 g (2.8 (2 to 5)), male sex (2.7 (2 to 5)), gestation < 30 weeks (2 (1 to 4)) and no IAP (2 (1.04 to 4)). Regression coefficients were converted into scores of 6, 6, 3, 3, 2 and 2, respectively. Internal prediction accuracy was 86.5% and c statistic was 0.75 (95% CI 0.70 to 0.81, p < 0.001). Conclusions Vaginal examinations >= 3, clinical chorioamnionitis, birth weight < 1500 g, male sex, gestation < 30 weeks and no intrapartum antibiotics were independent risk factors for EONS among preterm infants of <= 34 weeks' gestation.