Chorioamnionitis and early-onset neonatal infection.

Abstract

Chorioamnionitis is associated with early-onset neonatal infection, but only a small fraction of women with chorioamnionitis has an infected infant. US guidelines recommend empiric antibiotics for well-appearing infants of mothers with chorioamnionitis. A 4-year US study of early-onset neonatal infection (defined as positive blood or CSF culture ≤72 h) collected data about clinical or histopathological maternal chorioamnionitis. An analysis aimed to determine how many chorioamnionitis-exposed infected infants were asymptomatic at birth.1 The incidence of early-onset infection was 1.02 per 1000 live births (389 episodes in 396 586 births). The mothers of 60% of infected infants had a diagnosis of chorioamnionitis; 29 (13%) of 229 had no reported symptoms at 6 h, and 21 (9%) remained symptom free at 72 h. Asymptomatic infants were no more likely than symptomatic infants to have received intrapartum antibiotics. Most infected infants (65%) were born preterm, 91% of them at 22–33 weeks' gestation, itself a risk factor for infection likely to warrant starting antibiotics. The authors estimated that, if current guidelines were followed and depending on chorioamnionitis prevalence, 60 to 1400 newborns would receive antibiotics for each infected asymptomatic newborn. Some chorioamnionitis-exposed newborns with culture-confirmed early-onset neonatal infection are asymptomatic, but empiric treatment on the basis of chorioamnionitis also results in treating large numbers of asymptomatic infants.