Recent study has shown that intake of methamphetamine during pregnancy can lead to brain abnormalities in children. Methamphetamine is a highly addictive stimulant that is injected, snorted, smoked or swallowed by the people.

Research team led by Dr. Linda Chang of the University of Hawaii compared data collected from 29 3- and 4-year-olds whose mothers used methamphetamine during pregnancy with 37 children of the same ages whose mothers did not use the drug.

Research team used a new magnetic resonance imaging, or MRI, technique known as diffusion tensor imaging to look for abnormalities in tiny brain structures. Brain scans of the children revealed that there was a difference in the white matter structure, which carries messages across the brain, and maturation of brains of children with prenatal exposure to drug.

Dr. Linda Chang said: "Animal studies have shown if you give meth to an animal, their brain tissue becomes more densely packed."

She said her team now plans to follow the children as they grow to see if these differences persist.