Pregnant mice given a single dose of methamphetamine had babies who suffered from developmental problems and impaired motor skills, according to a University of Toronto researcher.

The Saskatoon Star Phoenix reported March 19 that researchers believe that meth use releases free radicals in the brain, which can cause a variety of damage, including to DNA. Fetal brains have less ability than adult brains to counteract free radicals, said University of Toronto researcher Peter Wells.

In mice, the harmful effects of prenatal meth use appear to be permanent. Wells said it's not clear if the animal studies can be applied to human drug use, however. "It's very difficult to know the (troubles) that meth causes in humans because there's very little documentation about what they're exposed to," he said.