Smoking during pregnancy poses a host of risks to both mother and child. Less oxygen for the baby, more toxic chemicals in the bloodstream, potential lung damage—these and other concerns have been raised by groups ranging from the March of Dimes to the Centers for Disease Control.

Now researchers at the University have found another cause to pause: a link between smoking during pregnancy and psychological disorders in children and young adults. A yearlong study of lab mice indicates that heavy use of nicotine alters the formation of myelin, a fatty brain substance that insulates brain cell connections in regions associated with neurobehavioral development.

“Myelin deficits have been observed in adults with various psychiatric disorders,” says Ming Li, a professor in UVA’s Department of Psychiatry and Neurobehavioral Sciences. “Our findings suggest that abnormal myelination may contribute to the psychiatric disorders associated with maternal smoking.”

The study also found evidence that smoking during pregnancy affects male and female offspring differently. “We still have a lot of work to do to see why that is,” Li says.

“While further studies are necessary to determine a direct correlation of our initial findings, our research lends weight to the necessity of educating women to avoid smoking during pregnancy.”