Foetal anticonvulsant syndrome describes a group of disorders in which birth defects and developmental disorders occur in association with a characteristic facial appearance in children whose mothers took antiepileptic drugs during pregnancy. Information on the total number of individuals diagnosed in the United Kingdom with foetal anticonvulsant syndrome is not available, however epidemiological studies suggest that the incidence of birth defects in babies born to mothers receiving antiepileptic medicines is approximately two to three times higher than the background rate in the general population.
The UK Epilepsy and Pregnancy Register was established in 1996 in order to gather further information on the outcomes of pregnancies in women receiving antiepileptic medicines. All pregnant women taking antiepileptic medicines are encouraged to notify their pregnancy or allow their clinician to notify their pregnancy to this register. Findings from this register were published in 2005 and suggested that almost 96 per cent. of live-births born to women with epilepsy did not have a major birth defect. It also confirmed that the likelihood of a baby being born with a birth defect is increased if the woman is taking more than one antiepileptic medicine (polytherapy).
The best established risk of abnormalities is associated with sodium valproate. An increased incidence of birth defects (including head and face deformities, deformities of the bones, malformations of the arms and legs and defects of the spinal cord and spine such as spina bidifia) has been shown in children born to mothers who took sodium valproate during pregnancy. For sodium valproate taken as monotherapy, the report from the UK Epilepsy and Pregnancy Register suggests that approximately five babies are born with a major birth defect for every 100 women taking this drug. This risk increases to approximately nine in 100 at higher doses (over 1,000 mg per day).
The authorised product information on sodium valproate for prescribers and the patient information leaflet contain clear advice about its safety of use during pregnancy. This includes information about the potential for birth defects and recommends that any woman taking sodium valproate who is likely to become pregnant should receive specialist advice on these risks. There is also a recommendation that if taken during pregnancy sodium valproate should be used as monotherapy at the lowest effect dose. Folic acid supplementation prior to pregnancy is also recommended as this may reduce the risk of having a baby with spina bifida.
The National Institute for Health and Clinical Excellence has published a clinical guideline covering the diagnosis, treatment and management of epilepsies in adults and children. This clinical guideline specifically covers the treatment and management of epilepsy in pregnancy.