Interim results of a study being conducted by scientists at the University of Liverpool suggest that children aged three years and younger, who are born to women taking the anti-epileptic drug sodium valproate whilst pregnant, are likely to have an IQ of six to nine points lower than average.
The research, in collaboration with Emory University in the US and the Central Manchester University Hospitals NHS Foundation Trust, tested more than 300 three-year-olds in the UK and US, whose mothers took one of four anti-epilepsy drugs (AEDs) whilst pregnant.
The preliminary findings suggest that children exposed to the drug sodium valproate had lower IQ results than children exposed to other AEDs, regardless of the mother's IQ. The results also took dosage, duration of pregnancy and mother's consumption of folic acid whilst pregnant, into account.
Professor of Clinical Neuropsychology at the University, Gus Baker, said "Our research looked at how exposure to sodium valproate and other AEDs in the womb affected children's everyday life - in particular their IQ, memory and language abilities from one to six years of age."
Around 5,000 women with epilepsy become pregnant every year in the UK and the majority of these, including those on AEDs, will experience uncomplicated pregnancies and births. Previous research conducted by the team has already shown that children exposed to AEDs such as sodium valproate in the womb are more likely to suffer birth defects characterised by heart malformations, dysmorphic features and minor limb deformities.
Professor Baker added: "The answer is not as simple as to take women off AEDs altogether as the effects of suffering a seizure can also pose a risk for both mother and unborn child. It is vital that the research is now used to educate women with epilepsy before they start to plan for a family.
Women need to be aware of the risks so that they can make informed choices with the help and advice of experts. It is also important that women do not stop taking AED treatment without taking advice from their medical practitioner."
"It is important to stress that sodium valproate is used globally and it has a favourable safety profile for all adult patients who use it. It has a range of pharmaceutical uses including bipolar disorder, migraine, epilepsy, and in adults sodium valproate is extremely effective."