Anti-epileptic drugs like sodium valproate (VPA), taken during pregnancy, increases the risk of brain impairment in children, according to a University of Birmingham study.

Researchers said that prenatal exposure to VPA affects brain development and ups the risk of congenital malformations and neurodevelopmental difficulties, particularly with language skills.

This is the first study to directly analyse the neural effects in children born to epileptic mothers who took VPA during pregnancy.

For the study, the researchers compared structural brain scans of seven-year-old children, who were exposed to VPA before their birth, to a control group of children whose mothers did not take the medication.

The researchers found that the scans of children belonging to the first group showed an increased cortical thickness in the left inferior frontal gyrus and left pericalcarine sulcus. The hemispheric asymmetry found in areas of the brain related to language processing was also absent.

These brain regions play an important role in the development of language skills like verbal communication.

"This is only a small group, but nonetheless it represents an important first step in understanding how taking VPA during pregnancy might effect a child's brain development," Researcher Dr Amanda Wood said in a statement. "VPA remains an important medication for people with epilepsy. What this study really tells us is that further research is required so that all women with epilepsy can make informed decisions about their medication use during pregnancy."

Researchers suggest pregnant women to consult doctors before changing their medication.

The study is published in the journal Annals of Clinical and Translational Neurology.