Infants who are given general anesthesia more than once are twice as likely to have learning disabilities later on than children never exposed to the drugs, a new study suggests.
The results add to mounting evidence -- from experiments in animals and observational studies in humans -- that anesthesia might injure young developing brains.
"There's a persistent association between multiple anesthetic exposures during the first two years of life and subsequent problems with learning," lead author Dr. Randall Flick, a professor at the Mayo Clinic in Rochester, Minnesota, told Reuters Health.
Whether the anesthesia is actually causing those disabilities is not clear, and experts caution that these results should not influence doctors' and parents' decisions to treat children who need painful procedures.
"This should not get in the way of having children receive adequate surgical care," said Dr. Bob Rappaport, head of the US Food and Drug Administration's Division of Anesthesia, Analgesia and Addiction Products.
General anesthesia is used to make people unconscious, and therefore unable to experience pain sensations, during invasive or painful procedures.
In young animals, exposure to anesthetic drugs causes the normal process of pruning extra brain cells to become more pronounced and widespread, and the animals end up with learning and behavior problems later in life.
Flick and his colleagues compared the learning skills of 350 children who had received one or more doses of anesthesia before the age of two to 700 children who had never been put under.
The researchers only included children who were healthy and did not have long-lasting illnesses, which meant the reasons for the anesthesia were due to short-term, minor procedures such as putting in ear tubes or repairing a hernia.
Eighty-one of the kids who had had anesthesia developed a learning disability before the age of 19, while 138 children in the other group had learning disabilities.
Those figures translated to rates of disability that were about the same among children who had undergone one procedure with anesthesia and those who had never been exposed -- roughly 23 and 21 out of every 100 kids in each group, respectively.
But for children who had had two or more procedures with general anesthesia, the rate was higher: 36 out of every 100 kids had a learning disability.
Rappaport told Reuters Health the FDA is working to accelerate research on anesthesia in children. Flick is a member of an FDA advisory panel on the subject.
The current study, which was funded in part by the FDA, does not conclusively show that the drugs are to blame for the children's learning problems.
And, researchers note, the study's observational nature makes it impossible to tease apart the influence of the surgery itself from that of the medication.
For now, the panel recommends no change in the way anesthesia is used in children.
"We don't want parents to become excessively concerned about this and delay unneeded surgery," Flick told Reuters Health, "because the risk of delaying surgery would be greater than the risk of anesthesia exposure."