Birth defects risk doubled with valproate
Pregnant women treated for epilepsy with sodium valproate face more than double the risk of birth defects in their children than those on other anti-epileptic drugs, new research has found.
But the results for alternative drugs were better than expected and there is still 'a place for valproate in the treatment of epilepsy for both men and women', experts claimed.
The evidence helped prompt a move by the Committee on Safety of Medicines (CSM) last month described by researchers as 'somewhat proactive' to ban GPs from giving sodium valproate to women of childbearing age without specialist advice.
Interim results from the UK epilepsy and pregnancy register, the largest study of birth defects in children born to women with epilepsy, showed the rate of malformations in children born to mothers on valproate is more than twice as high (5.9 per cent of the sample) as those on carbamazepine (2.3 per cent) and lamotrigine (2.1 per cent).
But Dr Jim Morrow, consultant neurologist at the Royal Victoria Hospital, Belfast, who presented the findings at the International Epilepsy Congress in Lisbon earlier this month, said: 'The results are fairly encouraging on anti-epilepsy drugs. Neurologists always said that a woman on anti-epileptics carried a two to three times higher background risk of having a child with major malformation. This would mean a 3-9 per cent increase. This is only true for valproate, which is no worse than thought and the other drugs come off better than expected.'
He said the CSM was being 'somewhat proactive', but said it was reasonable that GPs should seek specialist advice on prescribing for women.
The ongoing study is monitoring anti-epileptic use and the incidence of major congenital malformation in children born to 3,301 women with epilepsy at three months post-delivery. Abnormalities include cardiac, neural tube defects and gastrointestinal tract abnormalities.
Early results also indicate the combination of lamotrigine and valproate should be avoided in pregnancy.