Children exposed to methamphetamine during pregnancy may suffer from altered brain development, Reuters reported April 15.

Researchers at the University of Hawaii, Honolulu assessed the brain structure of children who were exposed to methamphetamine during pregnancy and found that they had up to 4 percent less diffusion of molecules in brain white matter than those who were not exposed.

While it is unclear how methamphetamine exposure leads to lower brain diffusion, author Linda Chang said the condition usually indicates that nerve fibers are compacted.

"Methamphetamine use is an increasing problem among women of childbearing age, leading to an increasing number of children with prenatal meth exposure," Chang said. "But until now, the effects of prenatal meth exposure on the developing brain of a child were little known."

The findings were published online April 15, 2009 in the journal Neurology.