Mariela's post-cooling MRI looked normal, which suggested she wouldn't have any long-term cognitive problems due to the lack of oxygen, according to Ms. Peloquin.

WSJ: Hypothermia Cure for Babies: Cooling Infants to Battle Brain Damage

"Sometimes we look at it like a rebirth, " said Susan Peloquin, a UCSF neonatal intensive care nurse who specializes in hypothermia treatment and helped treat Mariela.

WSJ: Hypothermia Cure for Babies: Cooling Infants to Battle Brain Damage

She moved her fingers and squirmed, her mouth opening and her tongue rooting around normal behavior for a newborn and a very good sign of Mariela's prognosis, Ms. Peloquin said.

WSJ: Hypothermia Cure for Babies: Cooling Infants to Battle Brain Damage