Babies deprived of oxygen at the time of their birth can sometimes suffer brain damage later in their childhood. A new study shows how cooling these oxygen-deprived newborns dramatically increases their chances of survival without neurologic disabilities.

Called perinatal asphyxia, this lack of oxygen can happen if blood flow to the baby’s brain is temporarily cut off during delivery, such as a drop in the mother’s blood pressure. Depriving the brain of oxygen can lead to cell death and permanent neurological damage. 

To investigate if hypothermia can successfully interrupt these processes, Denis Azzopardi of King's College London and colleagues monitored 325 newborns at risk for brain damage who received either standard care or standard care with hypothermia. In the latter group, the babies’ body temperatures were reduced to 33 degrees Celsius for 72 hours within six hours after their birth; they were placed on a special mat or jacket that circulated cold water (pictured). Afterwards, they were slowly returned to a normal temperature of 37 degrees Celsius. 

When the children were six or seven years old, the team evaluated their neurocognitive function: looking at their performance in school, examining teacher and parent reports, and investigating the symptoms or severity of any disabilities. 

They found that 51.7 percent of infants treated with hypothermia survived and had an IQ of 85 or above, which is within the normal range -- compared to 39.4 percent of those treated with standard care.

Cooling significantly reduced the chances of cerebral palsy and other moderate to severe disabilities, and the children also showed improved motor functioning. However, there was no difference in mortality rate between the standard care and the hypothermia-treated groups, and the longer-term benefits remain unclear. 

"The bottom line,” study coauthor David Edwards of King’s College London tells Nature, “is that this doubles a child’s chance of normal survival." 

The study was published in the New England Journal of Medicine this week. 

Images: Medical Research Council (top) & Marianne Thoresen via University of Bristol (middle)