An anti-epilepsy drug first licensed in the UK in 1975 may cause long-term developmental problems in children born to pregnant women using it, suggest the results of a new study.
Epilepsy experts already believe there is a strong link between using drugs containing sodium valproate during pregnancy and dysmorphic features 鈥� such as eyes set wider apart and a thinned upper lip 鈥� in children born subsequently.
They have suspected that valproate use in pregnant mothers may also lead to longer term developmental problems in their children 鈥� but until now the evidence for this has been anecdotal.
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鈥淭he new research is saying something we鈥檝e guessed for a long time,鈥� says Tim Betts, a neuropsychiatrist at the University of Birmingham, UK. 鈥淣ow they鈥檝e measured it for the first time. It鈥檚 very important work.鈥�
The study, led by Naghme Adab from the Walton Centre for Neurology and Neurosurgery, Liverpool, UK, shows that children born to mothers who were on valproate when pregnant were eleven times more likely to have a verbal IQ score of 69 or below, compared with children born in the general population.
Malformed faces
The study of 249 children aged six to 16 revealed that 22% of the valproate group had an IQ below 69, compared with 8% of children born to mothers taking another anticonvulsant drug, carbemazepine. Only 2% of children from the general population scored this low.
The children born to mothers taking valproate were also much more likely to have dysmorphic facial features, with 44% suffering malformations. This compares to 9% of children born to mothers on carbemazepine and just 2% among children born to mothers with epilepsy but not taking any anti-epilepsy drugs.
鈥淰alproate is still the most effective drug for generalised epilepsy,鈥� says Gus Baker, one of the team from the University of Liverpool. 鈥淏ut a balance has to be struck between the potential effects of seizures on the developing brain of fetuses and the effects of this anti-epileptic drug.鈥�
The researchers caution that their results could be partly skewed by the fact that only 40% of the mothers contacted for the study actually responded 鈥� mothers who cooperated might be more likely to believe their children were harmed by anti-epilepsy drugs.
However, even if it is assumed the other 60% of children all had normal IQs, the children of valproate users would still be twice as likely to have a low IQ (below 79) than the general population, say the authors.
Warnings given
鈥淓pilepsy is the second most common cause of maternal deaths,鈥� Betts told New 杏吧原创. He cautions that women should not stop taking prescribed anti-epilepsy drugs during pregnancy without consultation, and adds that safe alternatives are available. 鈥淲hen we see women before pregnancy we invariably try to get them off valproate,鈥� he says.
Pharmaceutical giant Sanofi-Synthelabo, which manufactures sodium valproate under the trade name Epilim, also stresses that women should not come off valproate suddenly. It already warns of some of the risks of taking Epilim during pregnancy.
鈥淲omen of childbearing potential should not be started on Epilim without specialist neurological advice,鈥� states Sanofi鈥檚 product information. 鈥淲omen who are likely to get pregnant should receive specialist advice because of the potential teratogenic risk to the fetus.鈥�
鈥淭his is an important study and a useful contribution to our understanding of the risks and benefits of taking anti-epileptic drugs during pregnancy,鈥� a Sanofi-Synthelabo spokeswoman told New 杏吧原创. But she adds that epilepsy is a complex disorder, which can pose serious risks to both mother and unborn child if the mother were to suffer a seizure during pregnancy.
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