The association of histological chorioamnionitis and antenatal steroids on neonatal outcome in preterm infants born at less than thirty-four weeks' gestation

Background: Despite continuous research on the prevention of preterm labor, preterm delivery still occurs often. Different neonatal outcomes in association with chorioamnionitis might occur with the introduction of antenatal steroids. Objective: The purpose of this study was to determine the effect of chorioamnionitis on the outcome of preterm infants and the association of antenatal steroids in the presence of histological chorioamnionitis (HC). Methods: Two hundred and fifty-seven infants born at <34 weeks and admitted to Ewha Womans University Hospital from 2005 to 2010 were enrolled. They were divided into 2 groups, one with HC (n = 89) and the other without HC (n = 168). The clinical characteristics and outcomes of the preterm infants including sepsis, respiratory distress syndrome, intraventricular hemorrhage (IVH) and bronchopulmonary dysplasia (BPD) were analyzed. Results: HC was associated with IVH (p = 0.019) and early-onset sepsis (p = 0.038). In the HC group, the infants exposed to antenatal steroids developed BPD less than those without steroid exposure. The duration of mechanical ventilation was significantly decreased in the group with antenatal steroids. Conclusion: HC increased the incidence of early-onset sepsis and IVH in preterm infants of less than 34 weeks' gestation with a high odds ratio of 9.54. In the presence of HC, antenatal steroids significantly decreased the incidence of BPD.