Background

The National Center for Toxicological Research (NCTR) and investigators at several universities are conducting research regarding the effects of anesthetics on the nervous systems of developing animals. This research demonstrates that exposure to some anesthetics and sedatives may cause memory and learning difficulties and other harmful changes in the central nervous systems of laboratory animals. There is currently not enough data to prove or disprove whether similar effects occur in children.

The Research

In humans, the formation of brain structures and rapid brain growth starts early during pregnancy and continues for up to three years. In rats and mice, the comparable period of brain development is the first two weeks of life. In research studies, all of the anesthetics and sedatives commonly used in infants and children caused widespread loss of nerve cells and/or later abnormal behavior when administered during rapid brain growth in rodents. At this time, very limited data are available from studies of higher-level mammals, such as apes and monkeys. One study showed harmful effects to the nervous system in newborn monkeys given a commonly-used anesthetic.

For more information, see our Key Research Questions and Frequently Asked Questions.

My patient needs surgery, what should I do?

Postponing a necessary procedure may itself cause problems and would not be an option for the majority of children. For example, children with chronic ear infection may have delays in the development of speech related to problems with hearing. Surgery to treat this problem may improve learning whereas delay may result in long-term difficulties in the normal development of speech.

No studies show anesthetic drugs cause harmful effects to the nervous systems of children. One study describes learning disabilities after multiple anesthetics administered in infants and children prior to four years of age, but not from a single anesthetic. In that study, the researchers found that two exposures to anesthetics before age four increased the likelihood of future learning disabilities in reading, writing, and math by 50%. Three or more exposures created even greater risk for learning problems. Exposure for less than two hours did not appear to be linked to learning difficulties.