Supplementary Material for: Chorioamnionitis and Five-Year Neurodevelopmental Outcome in Preterm Infants

Background: Chorioamnionitis, a risk factor for preterm delivery, has been suggested to be associated with suboptimal neurological development in premature infants. Objective: To evaluate the association between chorioamnionitis and neurodevelopment in preterm infants at 5 years of age. Methods Very low birth weight and very low gestational age infants (n = 197) were recruited. Placental samples (n = 117) were evaluated for histological chorioamnionitis. Fetal histological chorioamnionitis was analyzed as a subgroup. The diagnosis of clinical chorioamnionitis was derived from medical records. Neurodevelopmental impairments were evaluated at 2 years of age, and cognitive development (n = 188) and neuropsychological performance (n = 193) were evaluated at 5 years of age. Results: There were no associations between histological or clinical chorioamnionitis and neurodevelopmental impairments at 2 years of age. Clinical chorioamnionitis and fetal histological chorioamnionitis were not associated with cognitive development or neuropsychological performance, but histological chorioamnionitis was associated with poorer cognitive outcome (regression coefficient = -7.22, 95% CI: -14.31 to -0.13) and weaker memory and learning functions (regression coefficient = -1.29, 95% CI: -2.40 to -0.18) at 5 years of age. Conclusion: Our study findings do not support clinical chorioamnionitis having a major independent role in the pathogenesis of neurodevelopmental problems in very preterm infants. Histological chorioamnionitis was associated with slightly less optimal performance at 5 years of age, but further studies are needed to verify the clinical significance of these findings.