Intrapartum Characteristics and Prognosis Associated With Neonatal Hypoxic-Ischemic Encephalopathy [15F

Abstract

INTRODUCTION: Neonatal hypoxic-ischemic encephalopathy (HIE) is associated with neonatal mortality, acute neurological injury and long-term neurodevelopmental disabilities; the role of intrapartum factors remains unclear. METHODS: This population-based cohort study employed linked obstetrical and newborn data derived from the Nova Scotia Atlee Perinatal Database (NSAPD, 1988-2015) and the Perinatal Follow-Up Program Database (2006-2015) for all pregnancies with live, non-anomalous newborns ≥35 weeks, born without pre-labor caesarean section. HIE was defined using standard definitions. Temporal trends in HIE incidence are described; Fisher's exact test and logistic regression were used to test the associations of intrapartum factors with HIE. RESULTS: The NSAPD identified 227 HIE cases out of a population of 226,711 pregnancies from 1988 to 2015, with a decrease in incidence from 0.14% to 0.1% through those years (P=0.01). Women with clinical chorioamnionitis in labor (OR 8.0, 95% CI 4.7-17), emergency operative delivery (OR 9.9, 95% CI 7.3-13), shoulder dystocia (OR 3.4, 95% CI 2.1-5.4), placental abruption (OR 19, 95% CI 12-29), and cord prolapse (OR 32, 95% CI 17-61) were more likely to have newborns with HIE. Two-thirds of newborns with HIE had an abnormal intrapartum FHR tracing. There was an infant mortality rate of 28% by age 3; neurodevelopmental outcomes in the surviving infants with HIE were normal in 33% and showed severe developmental delay in 37%. CONCLUSION: Overall, the rate of HIE was low in late-preterm and term infants. The identification of associated intrapartum factors should promote increased surveillance and careful management to optimize newborn outcomes.