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 < or =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 > or =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 > or =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 < or =34 weeks' gestation.