Results from a preliminary study conducted by France's drugs regulator ANSM indicate that in the period from 1967 to 2016, between 2150 and 4100 children in the country were born with at least one major congenital disorder after being exposed in the womb to valproate. The drug is manufactured in France by Sanofi under the name Depakine to treat epilepsy, and as Depakote and Depamide for use in treating bipolar disorders.
Data released last August for the initial part of the study showed that 14 322 pregnant women had been exposed to valproate and its derivatives between 2007 and 2014. In the latest analysis, which focussed on the period from 2011 to 2015, researchers examined data for nearly 2 million pregnant women and found that 2321 of them had been exposed to valproate.
Specifically, results illustrated that compared with the general population, the risk of major congenital malformations was four-fold higher among children born to women who used valproate to treat epilepsy, and two-fold higher among those born to women prescribed valproate for bipolar disorder. The regulator attributed the difference in risk to the lower level of valproate exposure among women treated for bipolar disorder, notably due to worse treatment adherence.
"The study confirms the highly teratogenic nature of valproate," remarked ANSM scientific director and co-author of the report Mahmoud Zureik, adding "the figure of about 3000 severe malformations is very high."
Commenting on the news, a Sanofi spokesman stated "we are aware of the painful situations faced by families whose children have problems that may be related to their mother's treatment of antiepileptic drugs during pregnancy." The spokesman added that as the risks associated with the use of valproate during pregnancy have become more apparent, Sanofi has been transparent with health authorities and worked to provide healthcare professionals with medical information.
ANSM is currently examining all anti-epileptic drugs regarding their teratogenic risk. The agency is also conducting an exploratory study of the neurological risks of valproate, with data expected in the second half of this year.
In 2013, the FDA issued a warning about the use of valproate anti-seizure products for the prevention of migraine during pregnancy, citing evidence that exposure to the drugs in utero was associated with reduced IQ scores in children. In addition, research data published in JAMA has indicated that exposure to valproate during pregnancy was associated with an elevated risk of autism.
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