Epilepsy drug linked to child deformities

Up to 4100 children in France suffered major malformations in the womb after their mothers took a treatment against epilepsy and bipolar disorders known as valproate between 1967 and 2016, France's drug regulator says.

Valproate, which has been manufactured in France by Sanofi under the brand Depakine for epilepsy, and Depakote and Depamide for bipolar disorders, is also believed to cause slow neurological development, says the French National Agency for Medicines and Health Products Safety.

Sanofi says it has been transparent with the authorities and has sought to keep doctors and patients abreast of medical information.

However, parents of those affected say the French state and Sanofi have been too slow to warn of the side effects, after the risks to fetuses became clear by the early 1980s.

The French drug authority says it will publish a study later this year on the neurological effects of valproate.

Valproate was approved as an antiepileptic drug in France in 1967 and has become one of the most widely prescribed treatments worldwide given its effectiveness on adult patients.

"We are aware of the painful situations faced by families whose children have problems that may be related to their mother's treatment of anti-epileptic drugs during pregnancy," a spokesman for Sanofi said in an emailed statement.