According to research published early online in Pediatrics, more than one exposure to general anesthesia puts infants at twice the risk for learning disabilities later on compared to children never exposed to the drugs.

Researchers investigated the association between exposure to anesthesia and subsequent:

• learning disabilities (LDs),

• receipt of an individualised education programme for an emotional/behaviour disorder (IEP-EBD), and

• scores of group-administered achievement tests.

Children born between January 1, 1976, and December 31, 1982, in Rochester, Minnesota, were the source of cases and controls (n=8548). Those exposed to anesthesia (n = 350) before the age of 2 years were matched to unexposed controls (n = 700) on the basis of known risk factors for LDs.

The researchers reported that among the 350 children exposed to anesthaesia/surgery, 81 developed LDs before the age of 19 (55 reading, 63 mathematics,64 written language), and among the 700 unexposed controls, 138 developed LDs (95 reading, 108 mathematics, 11 written language). The estimated cumulative incidence of LDs at 19 years was 21.3% for unexposed controls, 23.6% for those exposed once, and 36.6% for those with multiple exposures. Exposure to multiple, but not single, anesthetic/surgery significantly increased the risk of developing LDs (hazard ratio: 2.12 [95% confidence interval: 1.26–3.54]), even when accounting for health status.

The authors acknowledge that the current study does not conclusively show that the anaesthetics are to blame for the children's learning problems as the observational nature of the study makes it impossible to separate the influence of the surgery itself from that of the medication. Despite some limitations of the study, the researchers conclude that multiple exposures to anesthesia/surgery at an early age may adversely affect human neurodevelopment with lasting consequence, and further prospective studies are needed to confirm this.