Impact of maternal infection on outcomes in extremely preterm infants.

BACKGROUND: Infants born less than 29 weeks, or extremely preterm (EPT), experience increased morbidity and mortality. We hypothesized that exposure to maternal infection might contribute to neurodevelopmental impairment (NDI) or death at 2 years of age. METHODS: We conducted a retrospective cohort study of EPT infants from January 2010 to December 2020. Maternal data extracted included maternal infections, classified as extrauterine or intrauterine. Placental pathologic and infant data were extracted. The primary outcome was NDI or death at 2 years of age. RESULTS: 548 EPT infants were born to 496 pregnant people: 379 (69%) were not exposed to any documented maternal infection prenatally, 124 (23%) to extrauterine infection, and 45 (8%) to intrauterine infection. Neither diagnosis of maternal extrauterine nor intrauterine infection was associated with NDI or death at 2 years of age (p > 0.05). Acute histologic chorioamnionitis was associated with NDI or death at 2 years of age (p = 0.033). CONCLUSIONS: Maternal infection was not associated with NDI or death at 2 years of age in EPT infants. However, acute histologic chorioamnionitis was associated with this outcome. Further work should investigate the differential influence of infection and immune response with this pathology as relates to outcomes in EPT infants. IMPACT: Maternal infection was not associated with neurodevelopmental impairment (NDI) or death at 2 years of age in extremely preterm (EPT) infants. This is reassuring support that mechanisms at the maternal-fetal interface largely protect the EPT infant. However, pathologic findings of acute histologic chorioamnionitis were associated with NDI and death at 2 years of age. Further work should investigate the differential influence of infection and immune response with acute histologic chorioamnionitis on pathology as relates to outcomes in EPT infants.