A drug given to pregnant women for epilepsy and bipolar disorder caused "serious malformations" in up to 4,100 children, a French study suggests.
Mothers treated with valproate for epilepsy were up to four times likelier to give birth to a malformed child, the preliminary study found.
Introduced in France in 1967, valproate is prescribed widely worldwide.
Doctors in France are now advised not to give it to girls, women of childbearing age and pregnant women.
There was no immediate comment from the drug's manufacturer, Sanofi.
Smoking causes one in 10 deaths worldwide, a new study shows, half of them in just four countries - China, India, the US and Russia.
Despite decades of tobacco control policies, population growth has seen an increased number of smokers, it warned.
Researchers said mortality could rise further as tobacco companies aggressively targeted new markets, especially in the developing world.
The report was published in the medical journal The Lancet.