Mentally impaired children may result from expectant mothers taking the epilepsy drug valproate, according to a Neurodevelopmental Effects of Antiepileptic Drugs (Nead) study.
It reports in the New England Journal of Medicine that women of childbearing age should avoid taking the drug as a first-choice treatment for the condition.
A previous Nead study had also found links between the use of the drug and physical birth defects in newborns.
Says Professor Kimford Meador, from the Emory University School of Medicine in the US: `There are clear risks associated with valproate, and physicians have an obligation to inform women about them.
`It still has an important role in treating epilepsy, because some patients’ seizures can only be controlled with it. However, we are recommending that women with epilepsy try another drug first.`
Nead studied 300 children born between 1999 and 2004. It found that the average IQ was six to nine points lower in three-year-olds whose mothers took valproate than in those of mothers prescribed three other epilepsy drugs.