Placental findings among newborns with hypoxic ischemic encephalopathy.

To determine if pre-specified placental abnormalities among newborns with hypoxic-ischemic encephalopathy (HIE) differ compared to newborns admitted to a NICU without encephalopathy. Retrospective case-control study of newborns with HIE (2006-2014) and controls matched for birth year, gestational age, weight, and gender. One pathologist reviewed archived placental sections using pre-specified criteria. Sixty-seven newborns had HIE, 46 had available placentas and were matched with 92 controls. HIE had more maternal vascular malperfusion (46% vs 25%, p = 0.02), fetal vascular malperfusion (13% vs 0%, p < 0.001), and clinical abruption (22% vs 4%, p = 0.001). Controls had more normal placentas (29% vs 7%, p = 0.002), and chorioamnionitis (30% vs 9%, p = 0.005). Pre-specified placental lesions occurred in 87% of HIE and 65% of controls (p = 0.008) and identified >90% of primary diagnoses. Pre-specified placental lesions identified nearly all abnormalities in HIE and represented both acute and chronic processes.