Neonatal sepsis workups in infants ≥2000 grams at birth:: A population-based study

Background. Few data are available on the outcome of neonatal sepsis evaluations in an era when intrapartum antibiotic therapy is common. Methods. We identified all newborns weighing greater than or equal to 2000 g at birth who were ever evaluated for suspected bacterial infection at 6 Kaiser Permanente hospitals between October 1995 and November 1996, reviewed their records and laboratory data, and tracked them to 1 week after discharge. We analyzed the relationship between key predictors and the presence of neonatal bacterial infection. Results. Among 18 299 newborns greater than or equal to 2000 g without major congenital anomalies, 2785 (15.2%) were evaluated for sepsis with a complete blood count and/or blood culture. A total of 62 (2.2%) met criteria for proven, probable, or possible bacterial infection: 22 (.8%) had positive cultures and 40 (1.4%) had clinical evidence of bacterial infection. We tracked all but 10 infants (.4%) to 7 days postdischarge. There were 67 rehospitalizations (2.4%; 2 for group B streptococcus bacteremia). Among 1568 infants who did not receive intrapartum antibiotics, initial asymptomatic status was associated with decreased risk of infection (adjusted odds ratio [AOR]: .26; 95% confidence interval [CI]: .11-.63), while chorioamnionitis (AOR: 2.40; 95% CI: 1.15-5.00), low absolute neutrophil count (AOR: 2.84; 95% CI: 1.50-5.38), and meconium-stained amniotic fluid (AOR: 2.23; 95% CI: 1.18-4.21) were associated with increased risk. Results were similar among 1217 infants who were treated, except that maternal chorioamnionitis was not significantly associated with neonatal infection. Conclusions. The risk of bacterial infection in asymptomatic newborns is low. Evidence-based observation and treatment protocols could be defined based on a limited set of predictors: maternal fever, chorioamnionitis, initial neonatal examination, and absolute neutrophil count. Many missed opportunities for treating mothers and infants exist.