Placental pathology as a marker of brain injury in infants with hypoxic ischemic encephalopathy

Abstract

Background: Hypoxic Ischemic Encephalopathy (HIE) can lead to devastating consequences for the affected infant. Although therapeutic cooling benefits infants with moderate and severe HIE, differentiating mild from moderate-severe HIE may be challenging. The placenta reflects the fetal intrauterine environment and may reveal underlying processes that affect brain injury.

Aim: To describe placental histopathology using the Amsterdam Placental Workshop Group Criteria in different grades of HIE.

Study design: Retrospective cohort.

Subjects: Infants admitted to a tertiary care neonatal intensive care unit with a diagnosis of HIE between 2011 and 2016.

Outcome measure: Maternal and neonatal clinical variables and placental histopathology using the Amsterdam Placental Workshop Group Criteria were compared between mild and moderate-severe HIE. Mann-Whitney or t-test or ꭓ² were performed for bivariate associations as appropriate. To explain the relationship between placental pathology and severity of HIE odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated using logistic regression models.

Results: Of the 73 infants in the study, 23 had mild and 50 moderate-sever HIE. There was no difference in maternal and neonatal characteristics except for sentinel events which were higher in the moderate- severe group. On placental histopathology, acute inflammation, including fetal inflammatory reaction (FIR) were significantly higher in the moderate-severe group. After adjusting for confounders, FIR remained significantly associated with moderate-severe HIE, ORs 6.29, 95 % CI 1.5-25.

Conclusion: Our study demonstrates FIR in the placenta is associated with severity of HIE.

Keywords: Hypoxemic ischemic encephalopathy; Neonate; Placental pathology.