Sodium valproate: what are dangers of epilepsy drug for unborn babies?
The anti-epilepsy drug sodium valproate can cause birth defects, but data has revealed it is still being prescribed to pregnant women in the UK, with concerns also raised that they are not always given information about the risks. But what is the drug, and how big is the problem?
What is sodium valproate?
According to the NHS, sodium valproate can be given as a liquid, capsules, tablets or, in some cases, injections, and is used to treat epilepsy and bipolar disorder. It is sometimes also prescribed to people who have migraines. In the UK, brands that contain sodium valproate include Epilim and Dyzantil.
What are the dangers of sodium valproate being prescribed for pregnant women?
If taken by pregnant women, sodium valproate can cause birth defects, such as cleft palate, limb defects and heart problems, as well as developmental problems, including difficulties with language and learning. This pattern of outcomes is termed foetal valproate spectrum disorder (FVSD).
The Cumberlege Review, published in 2020, flagged that children with FVSD may also have bendy joints or differences in their facial features.
“In some cases, the developmental difficulties they experience may also meet the criteria for other diagnoses such as autism spectrum disorder or attention deficit hyperactivity disorder,” the report noted.
How many pregnant women have been given the drug?
According to the Medicines and Pregnancy Registry, a result of a collaboration between NHS Digital and the Medicines and Healthcare products Regulatory Agency (MHRA), exposure to sodium valproate during pregnancy has declined in recent years, with number of pregnant women prescribed the drug declining by 51% between the 2018-19 financial year and the 2020-21 financial year.
However, between April 2018 and
September 2021, 247 women were prescribed sodium valproate in a month in which they were pregnant.
The figure includes 138 women for whom a prescription issued in their first trimester was subsequently stopped, 98 for whom such a prescription was continued, 14 for whom the drug was prescribed during pregnancy after the first trimester and nine women who were prescribed the drug in the month they were expected to deliver their baby.
The team behind the registry note that not all pregnancies would have resulted in a birth, but say that the figures may be an undercount.
How many people are affected by foetal valproate spectrum disorder?
According to the Cumberlege review, by the time of the report, an estimated 20,000 people in the UK had been affected by in-utero exposure to sodium valproate.
The review adds that it is thought 10% of unborn children exposed to sodium valproate are likely to develop birth defects while 40% will have a developmental delay or autism.
“The system still does not know where all these valproate-affected children, now adults in many cases, are, or how to contact them to secure the proper diagnosis and assessment of their care needs,” the review noted.
What is being done?
A number of measures have been taken to try to prevent sodium valproate being given to pregnant women: in 2018 the MHRA stated that the drug must not be prescribed to those who could become pregnant unless they were on a pregnancy prevention programme.
The valproate pregnancy prevention programme sets out, among other actions, that women and girls must always use effective contraception while taking the drug, with patients and their healthcare professional needing to sign a risk acknowledgment form every year.
Among actions for pharmacists, the MHRA stated: “Make sure you provide every patient with the statutory patient information leaflet – even if you have to split a pack.”
After the Cumberlege review, the Valproate Safety Implementation Group was set up, with initiatives including sending a letter from the NHS to all women and girls aged 12 and over who have a current prescription for sodium valproate, flagging the risks posed to unborn babies.
However, the latest data from the Medicines and Pregnancy Registry suggests that despite such actions, some pregnant women are still being prescribed sodium valproate, with an investigation by the Sunday Times reporting that in some cases, the drugs were not accompanied by information leaflets or warnings on boxes.