Neonatal encephalopathy, sentinel events, and the placenta

Objective: To examine the frequency and types of placental pathology observed in encephalopathic newborns presenting for therapeutic hypothermia. Study Design: Between May 2006 and April 2010, 140 term newborns with neonatal encephalopathy were admitted for cooling. The presence or absence of recognized asphyxial ("sentinel") birth events was noted. Placental pathology was categorized as vascular, inflammatory, or other. Result: Placental surgical pathology reports were available for 100 newborns, of whom 51% had sentinel events. Abnormalities were reported in 51% of placentas, 29% with and 73% without sentinel events (p = 0.0001). Inflammatory pathology was more frequent in infants without sentinel events (43% vs. 14%, p = 0.0016), especially in infants with pH below 7.0 (p = 0.012). Conclusion: Placental pathology was common in infants with neonatal encephalopathy admitted for therapeutic hypothermia, especially in those with no clinically recognized sentinel birth events. Severe acidosis was often observed in infants without sentinel events who had inflammatory placental pathology.