FRIDAY, Sept. 1, 2017 (HealthDay News) -- Babies who receive general anesthesia for surgery before they're 1 year old may have less white matter in their brains, a small study suggests.
The researchers said they also found that the integrity, or structure, of the white matter might have been affected.
White matter is tissue that connects different parts of the brain.
"The most rigorous previous study in humans looked at the effects of general anesthesia during infancy on cognitive [brain] functions of 2-year-olds, and results showed no effect," said study first author Robert Block. He is an associate professor of anesthesia at the University of Iowa Carver College of Medicine.
"This study is looking specifically at the white matter structure and how it is affected," Block said in a university news release.
The University of Iowa Health Care study included 34 healthy children aged 12 to 15. Half of these children had surgery under general anesthesia within their first year of life. The remaining 17 children did not.
The researchers performed brain scans (MRIs) on each of the children to assess the possible long-term effects of general anesthesia.
The MRIs showed the volume and integrity of white matter was, on average, 1.5 percentage points lower among the children who had undergone surgery with general anesthesia as infants.
The significance of this discrepancy remains unclear, the researchers said. Larger studies are needed to check the long-term effects of general anesthesia on young children, they added.
"There is the question of whether this is functionally significant, and we don't yet have the answer to that," Block said. "That's one reason we need to look at a larger group."
The findings come on the heels of a warning from the U.S. Food and Drug Administration in April that prolonged or repeated use of general anesthesia among children younger than 3 could have negative effects on the brain.
"The FDA may have jumped the gun a little in their warning because they based it mostly on animal studies," said Block.
"The topic needs a lot more research specifically examining human brain development," he added.
The study was published online recently in the journal Anesthesiology.
The U.S. National Institute of General Medical Sciences has more about general anesthesia.