Chorioamnionitis and culture-confirmed, early-onset neonatal infections

Background: Current guidelines for prevention of neonatal group B streptococcal disease recommend diagnostic evaluations and empirical antibiotic therapy for well-appearing, chorioamnionitis-exposed newborns. Some clinicians question these recommendations, citing the decline in early-onset group B streptococcal disease rates since widespread intrapartum antibiotic prophylaxis implementation and potential antibiotic risks. We aimed to determine whether chorioamnionitis-exposed newborns with culture-confirmed, earlyonset infections can be asymptomatic at birth. Methods: Multicenter, prospective surveillance for early-onset neonatal infections was conducted during 2006-2009. Early-onset infection was defined as isolation of a pathogen from blood or cerebrospinal fluid collected ≤72 hours after birth. Maternal chorioamnionitis was defined by clinical diagnosis in the medical record or by histologic diagnosis by placental pathology. Hospital records of newborns with early-onset infections born to mothers with chorioamnionitis were reviewed retrospectively to determine symptom onset. Results: Early-onset infections were diagnosed in 389 of 396 586 live births, including 232 (60%) chorioamnionitis-exposed newborns. Records for 229 were reviewed; 29 (13%) had no documented symptoms within 6 hours of birth, including 21 (9%) who remained asymptomatic at 72 hours. Intrapartum antibiotic prophylaxis exposure did not differ significantly between asymptomatic and symptomatic infants (76% vs 69%; P =.52). Assuming complete guideline implementation, we estimated that 60 to 1400 newborns would receive diagnostic evaluations and antibiotics for each infected asymptomatic newborn, depending on chorioamnionitis prevalence. Conclusions: Some infants born to mothers with chorioamnionitis may have no signs of sepsis at birth despite having culture-confirmed infections. Implementation of current clinical guidelines may result in early diagnosis, but large numbers of uninfected asymptomatic infants would be treated.