Association of chorioamnionitis and its duration with neonatal morbidity and mortality.

To investigate the association of chorioamnionitis, and secondarily its duration, on neonatal adverse outcomes for infants born <34 weeks vs. ≥34 weeks.A secondary analysis from the observational U.S. Consortium on Safe Labor Study. The exposure was chorioamnionitis, and secondarily, its estimated duration. The composite outcome included pneumonia, seizure, necrotizing enterocolitis, sepsis, periventricular/intraventricular/cerebral hemorrhage, mechanical ventilation, and neonatal death. Multivariable logistic regression with generalized estimating equations was used, stratified by gestational age at delivery.Among 221,274 deliveries, the odds of the neonatal adverse outcome <34 weeks was 2-fold higher among infants exposed to chorioamnionitis vs. those who were not (62.0 vs. 47.7%; AOR: 1.86; 95%CI: 1.25-2.75), and was ~3.5-fold higher ≥34 weeks (9.2 vs. 2.5%; AOR: 3.34; 95% CI: 2.35-4.76). The estimated duration of chorioamnionitis did not change the above associations.Chorioamnionitis was associated with an approximately 2- and 3.5-fold increased odds of neonatal adverse outcomes <34 and ≥34 weeks, respectively, regardless of its estimated duration.