More than 10,000 pregnant women in France took Sanofi's anti-epilepsy drug Depakine between 2007 and 2014 although the risk of fetus malformation was known, according to a study quoted by French satirical weekly Le Canard Enchaîné, reports Reuters.
The weekly reported that the French health ministry had delayed publication of the study, which the ministry denied.
The ministry confirmed in a statement that a study was done by national drug agency ANSM and health insurance agency CNAMTS but added that it had not been hidden from families and that a first part of the study would be presented on August 24.
The ministry said it would study measures that needed to be taken and that the full study and an action plan based on it would be made public in September.
Sanofi said the company was not aware of the data in the study and could not comment on it.
A Sanofi spokeswoman told Reuters that the firm had become aware of the risk of fetus malformation in the 1980s and that these had been spelled out in the drug's documentation.
She added that from around 2003, Sanofi became aware that the drug - based on sodium valproate - also impacted the fetus' neurological development and could lead to autism or learning difficulties.
She said these potential side effects had been communicated to health authorities, which updated the drug's documentation in 2006. She specified that drug documentation needs to be approved by health authorities in France.