Design Multicenter, international, randomized controlled trial.
Setting Neonatal intensive care units in Australia, New Zealand, Canada, and the United States (N = 28) from February 2001 through July 2007.
Participants Newborns of 35 weeks' gestation or more, with indicators of peripartum hypoxia-ischemia and moderate to severe clinical encephalopathy, randomly allocated to hypothermia (n = 110) or standard care (n = 111).
Intervention Whole-body hypothermia to 33.5°C for 72 hours or standard care (37°C). Infants who received hypothermia were treated at ambient environmental temperature by turning off the radiant warmer and then applying refrigerated gel packs to maintain rectal temperature at 33°C to 34°C.
Main Outcome Measures Death or major sensorineural disability at 2 years of age.