The impact of histopathological fetal inflammatory response syndrome on acute neonatal outcomes: a multisite cohort study.

OBJECTIVE: To examine the impact of histopathological Fetal Inflammatory Response Syndrome (FIRS) on acute clinical outcomes in very preterm neonates. STUDY DESIGN: This was a two site cohort study based in tertiary maternity units in Dublin, Ireland. Admitted neonates with placental histology and without congenital anomalies < 32 weeks corrected gestational age born between 2018-2022 (n=955) Were assessed for exposure to Amsterdam consensus guideline defined FIRS and consequent acute neonatal outcomes by both univariate and multivariate methods. RESULTS: While univariate analysis showed an increased incidence of death and BPD, multivariate analysis adjusting for gestational age and birth weight demonstrated that very preterm neonates exposed to histopathological FIRS are at a lower risk of bronchopulmonary dysplasia, composite death or bronchopulmonary dysplasia and RDS requiring surfactant. Neonates exposed to FIRS were born earlier and smaller than their peers who were not, and when adjusting for gestational age there was no increase in odds of severe IVH, days of mechanical ventilation or diagnosis of sepsis. CONCLUSION: Very preterm neonates exposed to FIRS are at lower risk of developing death or bronchopulmonary dysplasia and requiring surfactant when adjusting for age and birth weight. No other acute outcomes were statistically significantly different.