A new study has found that methamphetamine - the addictive stimulant drug - during pregnancy causes abnormal brain development in children.

This study is the first of its kind to examine the effects of methamphetamine use during pregnancy.

"Methamphetamine use is an increasing problem among women of childbearing age, leading to an increasing number of children with prenatal meth exposure. But until now, the effects of prenatal meth exposure on the developing brain of a child were little known," said study author Linda Chang, MD, with the John A. Burns School of Medicine, University of Hawaii at Manoa in Honolulu.

For the study, researchers conducted brain scans on 29 three and four-year-old children whose mothers used meth while pregnant and 37 unexposed children of the same ages.

The MRI scans used diffusion tensor imaging to help measure the diffusion of molecules in a child's brain, which can indicate abnormal microscopic brain structures that might reflect abnormal brain development.

The scans revealed that children with prenatal meth exposure had differences in the white matter structure and maturation of their brains compared to unexposed children.

Researchers found that children with prenatal meth exposure had up to four percent lower diffusion of molecules in the white matter of their brains.

"Our findings suggest prenatal meth exposure accelerates brain development in an abnormal pattern. Such abnormal brain development may explain why some children with prenatal meth exposure reach developmental milestones later than others," said Chang.