TORONTO — A single dose of the drug speed during pregnancy could be enough to cause long-term problems in babies, according to University of Toronto researchers.

Pregnant mice exposed only once to methamphetamine had offspring with reduced motor co-ordination and other neurodevelopmental effects.

"We've known for a while that meth abuse during pregnancy is associated with low birth weight, cleft palates and other malformations, but this is the first research demonstrating that even a single exposure can cause long-term damage,'' Peter Wells, a University of Toronto pharmacy and pharmacology professor, said Tuesday in a news release.

"It's pretty remarkable that a single low dose can have such an effect.''

He said the findings are of particular concern because of an increasing use of so-called club drugs, like speed, by women of child-bearing age. And it appears the developing child is vulnerable from the embryonic stage -- before a woman may even know she is pregnant -- through to the later fetal period.

"It has clinical implications, because it shows that the fetus is exquisitely sensitive,'' Wells said.

The research led by Wells is published in the August issue of Free Radical Biology and Medicine.

The researchers believe a developing fetus can be affected because it hasn't yet produced the enzymes that protect it against free radicals.

Wells plans to study women and infants who have been exposed to speed or similar drugs to see if the human damage is consistent with his mouse findings.

He will also try to determine whether the methamphetamine causes other lasting damage in mice, affecting such things as learning and memory.

The research was supported by a grant from the Canadian Institutes of Health Research.