Effect of acute histologic chorioamnionitis on bronchopulmonary dysplasia and mortality rate among extremely low gestational age neonates: A retrospective case–control study

Abstract Objective To evaluate whether acute histologic chorioamnionitis (HCA) diagnosed in the placenta may be associated with an increased occurrence of bronchopulmonary dysplasia (BPD) or death among extremely low gestational age neonates (ELGAN). Methods This Italian single‐center case–control retrospective study involved ELGAN admitted to the neonatal intensive care unit between January 2019 and June 2022. Infants born from pregnant women with acute and severe HCA, identified as stage ≥2 and grade 2 HCA, (HCA‐infants) were compared with infants of pregnant women without chorioamnionitis or with stage 1, grade 1 chorioamnionitis (no‐HCA‐infants). Results Among 101 eligible ELGAN, 63 infants had complete clinical and histologic data relevant to the study: thirty infants were included in the HCA‐infants group and 33 in the no‐HCA‐infants group. Neonatal and maternal demographic and clinical characteristics were similar between the two groups. Infants born from mothers with acute and severe HCA had significantly higher occurrence of composite BPD or death (18 [60%] vs. 9 [27%]; P = 0.012), as well as higher incidence of severe forms of BPD (6 [30%] vs. 2 [6%]; P = 0.045). In multiple logistic regression analysis, after adjustment for confounding covariates, HCA was an independent risk factor for BPD or death (OR, 4.49; 95% CI: 1.47–13.71). Conclusions This is the first study showing that in utero exposure to acute and severe HCA is an independent risk factor for the occurrence of composite BPD or death among ELGAN.