A new study out of the University of Cincinnati suggests that kids who need general anesthesia before the age of 4 might suffer the consequences years later with lower IQs.

In the study published in Pediatrics, researchers looked at 106 kids ages 5 to 18, half of whom had surgery before their fourth birthday, reports Medical News Today.

Generally speaking, the kids who had been under anesthesia scored worse on intelligence tests and in listening comprehension, and they had less gray matter in two areas of the brain (the cerebellum and occipital cortex), reports HealthDay News.

All of the kids in the study were still in the normal range for IQs, but the researchers found that the anesthesia kids consistently scored about 5 or 6 points lower.

"The very receptors that anesthetics act on to produce unconsciousness during surgery are also important for stimulating neurons to form proper connections and to survive," says study author Andreas Loepke.

"Anesthetic exposure may interfere with normal brain development." In a post at Eureka Alert, the team even puts a societal cost on the problem of $540 billion, based on earlier research suggesting that the loss of one IQ point translates to a lifetime earnings drop of $18,000.

So what to do? These are typically unavoidable surgeries, but the study shows the importance of figuring out safer protocols for kids—maybe more regional anesthetics instead of general anesthesia, or methods to limit the damage, for example, reports the Columbus Dispatch.

(A previous study looked at the scary-sounding problem of people waking up during surgery.)

This article originally appeared on Newser: Anesthesia May Harm Young Kids' Brains

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