According to American scientists, women who took an epilepsy drug during their pregnancy are at greater risk of having children with lower IQ.
In question is the drug valproate (already at the center of a British court action after claims that it has damaged children). Valproate seems to double the chance that the woman's child will be born with mental retardation.
Around 140 British families claim that their children are suffering from fetal anti-convulsant syndrome because their mothers took valproate during pregnancy. The syndrome includes a range of neural, behavioral and physical disorders such as cleft palate and spina bifida, learning difficulties, behavioral problems and abnormalities in movement, speech, vision and hearing.
Many mothers were prescribed the brand Epilim, made by Sanofi-Synthelabo, though the drug is also available in generic forms. As of now, Sanofi is the only company involved in the court action, with a trial date set for October 2008.
Lead researcher Kimford Meador, of the University of Florida in Gainesville, looked at IQ results of 187 children born to mothers who had taken the epilepsy drugs carbamazepine, lamotrigine, phenytoin, or valproate during pregnancy.
The results, presented yesterday at the American Academy of Neurology's annual meeting in Boston, showed that 24 percent of the children of mothers who took valproate had an IQ low enough to be defined as mentally retarded. This was against 12 percent for carbamazepine, 9 percent for lamotrigine, and 12 percent for phenytoin.
The results are published in the journal Neurology.
Children whose mothers took carbamazepine scored an average of 93 points on the IQ tests, those on phenytoin 93, lamotrigine 96, and 84 for valproate.
Says Meador: "Our findings are consistent with other studies, which have shown valproate poses an increased risk for fetal death and birth defect."
Yet, Ingrid Burns of the British Epilepsy Association adopts a middle path: "We believe there should be a balance struck between the potential effects of seizures on the developing brain of fetuses and the effects of valproate. While this is very concerning, it has to be said that valproate is a highly effective anti-epileptic drug."
Meador urges doctors to talk to their patients about the risks associated with valproate. "Valproate should not be used as the drug of first choice for women of child bearing potential, and when used, its dosage should be limited if possible."
Ms Burns agrees that women with epilepsy should be counseled before embarking on a pregnancy: "What we don't want is to scare people to stop people taking this drug suddenly because that can result in seizures and, potentially, deaths."
A Sanofi-Synthelabo spokeswoman was quoted: " The appropriate treatment of epilepsy during pregnancy is a highly complex area and Sanofi-Synthelabo . would urge patients not to make sudden changes to their medication without first discussing them with their doctor."