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Valproate in pregnancy linked to raised autism risk

But women need to balance this against benefits of seizure control

Louise Prime

Wednesday, 24 April 2013

Children of women with epilepsy who take valproate during pregnancy are significantly more likely to develop autism than children whose mothers do not use the drug, research has shown. But the authors of the study, published today in JAMA, warn that women being counselled about taking valproate during pregnancy need to balance these risks against the benefits that the drug brings in terms of seizure control.

Researchers examined data taken from national register on a total of 655,615 children born alive in Denmark between 1996 and 2006. They assessed the effect of exposure to valproate during pregnancy on a child’s risk of later being diagnosed with autism spectrum disorders – childhood autism, Asperger syndrome, atypical autism and other or unspecified pervasive developmental disorders. Children were followed up until a mean of nearly 9 years old.

Children who had been exposed to valproate during pregnancy had an absolute risk of 4.42% for autism spectrum disorder – 2.9 times the risk seen in unexposed children. They had an absolute risk of 2.50% for childhood autism – 5.2 times the risk in unexposed children. Children whose mothers used valproate during pregnancy also had higher risks than those mothers had previously used the drug, but had stopped before becoming pregnant.

The researchers wrote: “Maternal use of valproate during pregnancy was associated with a significantly increased risk of autism spectrum disorder and childhood autism in the offspring, even after adjusting for maternal epilepsy.” But they added that women with epilepsy being counselled about using valproate in pregnancy should bear in mind that the absolute risk of one of these disorders was less than 5%.

They said: “For women of childbearing potential who use antiepileptic medications, these findings must be balanced against the treatment benefits for women who require valproate for epilepsy control.”

The authors of an accompanying editorial warned: “The use of valproate in women of childbearing potential should be minimised. Alternative medications should be sought. If no alternative effective medications can be found, the lowest effective dose of valproate should be used … delaying discussions of treatment risks until a pregnancy is considered will leave a substantial number of children at unnecessary risk.”

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