HealthDay News — Children who receive general anesthesia during surgery before they turn 4 years of age may later score slightly lower on listening comprehension and performance IQ, compared to children who had never had general anesthesia; however, overall IQ scores appear to remain within the normal range. These findings were published online in Pediatrics.

Andreas Loepke, MD, PhD, a professor of clinical anesthesia and pediatrics at the University of Cincinnati College of Medicine, and colleagues compared 53 children who had undergone surgery using general anesthesia before they were 4 years old with 53 children who had never been exposed to general anesthesia. 

Each child from the first group was matched to a child in the second group according to age, sex, socioeconomic status, and being left- or right-handed.

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All of the children underwent IQ and language development testing as well as magnetic resonance imaging. The scores for all the children in both groups were within the normal range. But the children with a history of surgery had listening comprehension and performance IQ scores that averaged 3 to 6 points lower than the children without surgery. In addition, lower performance IQ and listening comprehension were associated with lower gray matter density in the occipital cortex and cerebellum, the researchers found.

“It is difficult to see whether this decrease had any functional effect for an individual child,” Loepke told HealthDay. But, he added, “these concerns make it obvious that a lot more research is needed to better understand the effects of anesthetics on brain development.”


  1. Backeljauw B et al. Pediatrics. 2015; doi:10.1542/peds.2014-3526.