The epilepsy drug valproate has been responsible for between 2,150 and 4,100 severe birth defects in children born in France since it was launched in 1967, according to a study by French medicine and health authorities.
The severe birth malformations include spina bifida, cleft palate and defects of the heart and genital organs. The risk of autism and developmental problems was also found to be higher.
The joint report from the French drug regulator (L’Agence nationale de sÃ©curitÃ© du mÃ©dicament et des produits de santÃ© (ANSM)) and the national health insurance administration (la Caisse Nationale de l’Assurance Maladie des Travailleurs SalariÃ©s (CNAMTS)) says that between 1967 and 2016, between 64,100 and 100,000 pregnancies in France were exposed to valproate, resulting in 41,200 to 75,300 live births.
The vast majority of the birth malformations occurred in children born to women who took the drug as a treatment for epilepsy while pregnant. These women were four times more likely than women in the general population to give birth to babies with severe congenital malformations.
From the late 1970s, valproate was also prescribed in France to treat bipolar disorder, and these women were twice as likely as the general population to give birth to babies with severe congenital malformations.
The report suggests that the difference in raised risk for the two conditions may be the result of women treated for bipolar disorder having a lower exposure to valproate than those treated for epilepsy, because non-adherence and treatment interruptions are more frequent in treatment for bipolar disorder than they are for epilepsy.