Histological Characteristics of the Fetal Inflammatory Response Associated with Neurodevelopmental Impairment and Death in Extremely Preterm Infants

Objective To test the hypothesis that increasing severity of the fetal inflammatory response (FIR) would have a dose-dependent relationship with severe neurodevelopmental impairment or death in extremely preterm infants. Study design We report 347 infants of 23-28 weeks gestational age admitted to a tertiary neonatal intensive care unit between 2006 and 2008. The primary outcome was death or neurodevelopmental impairment at the 18- to 22-month follow-up. Exposure status was defined by increasing stage of funisitis (stage 1, phlebitis; stage 2, arteritis with or without phlebitis; stage 3, subacute necrotizing funisitis) and severity of chorionic plate vasculitis (inflammation with or without thrombosis). Results A FIR was detected in 110 placentas (32%). The rate of severe neurodevelopmental impairment/death was higher in infants with subacute necrotizing funisitis compared with infants without placental/umbilical cord inflammation (60% vs 35%; P < .05). Among infants with stage 1 or 2 funisitis, the presence of any chorionic vasculitis was associated with a higher rate of severe neurodevelopmental impairment/death (47% vs 23%; P < .05). After adjustment for confounding factors, only subacute necrotizing funisitis (risk ratio, 1.87; 95% CI, 1.04-3.35; P = .04) and chorionic plate vasculitis with thrombosis (risk ratio, 2.21; 95% CI, 1.10-4.46; P = .03) were associated with severe neurodevelopmental impairment/death. Conclusion Severe FIR, characterized by subacute necrotizing funisitis and severe chorionic plate vasculitis with thrombosis, is associated with severe neurodevelopmental impairment/death in preterm infants.