Association of Histologic Chorioamnionitis with Perinatal Brain Injury and Early Childhood Neurodevelopmental Outcomes among Preterm Neonates

Acute chorioamnionitis refers to the neutrophilic inflammation of the placental tissues thought to result from an ascending bacterial infection. It is considered a major factor associated with pretermbirth and has been estimated to occur in 40%to 80% of preterm deliveries. Chorioamnionitis is associated with several adverse neonatal outcomes, including respiratory distress syndrome, sepsis, bronchopulmonary dysplasia, and death. Clinical studies examining brain injury and neurodevelopmental outcomes among infants with chorioamnionitis have yielded inconsistent results. Most of these studies have focused on intraventricular hemorrhage (IVH) and cystic periventricular leukomalacia. Because the incidence of cystic periventricular leukomalacia has greatly decreased during the past decades concurrent with improvements in neonatal intensive care, punctate white matter injury (WMI) is increasingly recognized as the most prevalent pattern of brain injury among preterm neonates. The researchers performed a prospective cohort study conducted across 3 academic centers in Canada, the Netherlands, and the United States. Children who were born preterm (24-32 weeks' gestation) and who had undergone a placental pathologic evaluation, magnetic resonance imaging (MRI) as soon as clinically stable, and Bayley Scales of Infant and Toddler Development, 3rd Edition (Bayley III) assessments between 18 and 24 months' corrected age (CA) were included. Magnetic resonance imaging scans were assessed for grade of IVH and volume of punctate WMI. Data analysis occurred between December 2016 and January 2018. Final multivariable analyses examining the association of chorioamnionitis with motor and cognitive outcomes accounted for academic center and perinatal and postnatal factors. PunctateWMI volume and IVH detected on neonatalMRI scans were used tomeasure the results,withmotor and cognitive outcomes defined using Bayley III assessments conducted among these children between 18 and 24 months' CA. There were 448 preterm infants (24-32 weeks' gestation) in the total cohort. Infants were included in the analysis if they had undergone placental pathologic assessments, early brainMRI, and 18 to 24 months of follow-up.Among the cohorts fromthe 3 academic centers, infants with evidence of a congenital infection, genetic syndrome, or large parenchymal hemorrhagic infarction (>2 cm) were excluded. Each placenta was sent fresh for macroscopic and microscopic analyses, which were conducted using the same clinical protocols at each center. Histologic chorioamnionitis was defined by clinical pathologists using strict criteria and the degree of placental inflammation was scored