The risks of pregnant women taking a common epilepsy drug were kept from patients for 40 years, a hearing was told.

An estimated 20,000 British children have been severely harmed because their mothers took the drug sodium valproate during pregnancy.

Campaigners yesterday presented evidence to a hearing of the European Medicines Agency in London, revealing that regulators knew of problems as far back as 1973.

An estimated 20,000 British children have been severely harmed because their mothers took the drug sodium valproate during pregnancy

Even the drug’s manufacturer Sanofi was open about the risks.

Yet documents show UK officials decided at the time not to put the warnings on the packets for fear it ‘could give rise to fruitless anxiety’, the hearing was told.

It was not until 2015 that clear warnings were published.

Sodium valproate, which is sold under the brand name Epilim for epilepsy, migraine and bipolar disorder, can cause physical deformities in children whose mothers take it during pregnancy, as well brain damage and problems such as autism.

Babies exposed to the drug in pregnancy have a 30 to 40 per cent risk of serious developmental disorders and an 11 per cent risk of congenital malformations.

The most up-to-date advice from the UK’s Medicines and Healthcare products Regulatory Agency, issued two years ago, says it should not be given to women of childbearing age or during pregnancy unless alternative treatments are ineffective or not tolerated.

Catherine Cox, from the Foetal Anti-Convulsant Support Association for the UK, said warnings on valproate should have been issued to women more than 40 years ago.

‘These warnings could have and should have been given in 1974,’ she said.

‘A decision was taken not to publish them despite warnings by the manufacturer,’ she said.

She said documents from July 1973 showed that regulators decided not to warn patients directly of the harms for in case it worried them.

Health professionals were told at the time: ‘This compound has been shown to be teratogenic in animals, meaning it could harm the human foetus.’

But the Committee on Safety of Medicines, which existed before the MHRA, said the warning should ‘not go on the package inserts, so that there would be no danger of patients themselves seeing it.’

The licence issued in 1974 for Epilim, a trade name for sodium valproate, said doctors and pharmacists should use it only in severe cases of epilepsy or where there was no alternative.

Clare Pelham, from the Epilepsy Society, said women needed to be given the right information to make an informed choice.

She said it must become mandatory for GPs to call women in for a review every 12 months rather than issuing repeat prescriptions.

The charity also wants to see a national register created of women taking the drug.

Joanne Cozens, chairwoman of the Organisation for Anti-Convulsant Syndromes, said many women who take the drug are not aware of the risks.

She called for a ‘red alert system’ so pharmacists and medics were alerted when prescribing or handing over medicines.

She also accused Sanofi of indirectly lobbying to restrict transparency.

‘Sanofi have a loyal bunch of clinical experts promoting valproate and resisting warnings,’ she said.

‘I can see a few in the room today. You know who you are and we don’t trust you anymore because you are complicit in avoidable injury to children.’

But Dr Eric Teo, in charge of drug safety at Sanofi, told the hearing: ‘Sanofi had always provided the most up to date scientific information, with the approval of the health authorities.

Babies exposed to the drug in pregnancy have a 30 to 40 per cent risk of serious developmental disorders and an 11 per cent risk of congenital malformations

‘There is a consent form for doctors to review with patients, there are patient cards to take home and there is also a prominent warning on the outside of the box.’

‘Based on the best available data, it is clear that there is an increased risk in both congenital malformation and having below average developmental ability, including cognitive function, in children who are exposed to valproate during pregnancy.’

But he said for some women valproate is the only option.

‘Switching or discontinuing treatment before or during pregnancy carries the risk of recurrent seizures which could lead to brain damage or death.’

‘It should be remembered that valproate is widely accepted as a life-saving medicine. It is listed as an essential medicine by the World Health Organisation.’

The inquiry marks the first time the European Medicines Agency has held a public hearing over safety concerns linked to a drug. Usually its committee meets behind closed doors.

Its Pharmacovigilance Risk Assessment Committee will now consider the evidence heard and publish its decision in the coming months as to what further measures are needed to warn women of the risks.