Impact of fetal inflammatory response on the severity of necrotizing enterocolitis in preterm infants

Objective: Neonates born with fetal inflammatory response (FIR) are at increased risk for adverse neonatal outcomes. Our objective was to determine whether FIR and its severity is associated with severity of necrotizing enterocolitis (NEC) in preterm infants. Methods: A case-control retrospective study of infants <33 weeks gestational age or <1500 g birthweight, including 260 with stage I–III NEC and 520 controls matched for gestational age. Placental pathology was evaluated, and FIR progression and its severity were defined according to Amsterdam classification. Results: In this study, mild FIR (i.e., stage 1 FIR) was present in 52 controls (10.0%) and 22 infants with stage I–III NEC (8.5%), while moderate to severe FIR (i.e., ≥stage 2 FIR) was present in 16 controls (3.1%) and 47 infants with stage I–III NEC (18.1%). Both stage and grade of FIR were associated with stage of NEC (P < 0.001). On multinomial logistic regression, stage III NEC was associated with stage of FIR (P < 0.001). Conclusion: This is the first report demonstrating the association between progression and increasing severity of FIR and stage of NEC. Impact: Fetal Inflammatory Response (FIR) and its progression and severity are associated with the stages of necrotizing enterocolitis (NEC).This is the first study demonstrating the impact of progression and severity of FIR on stage III NEC.These observations provide additional insight into understanding the impact of intrauterine exposure to inflammation on the severity of NEC in preterm infants.