Women with epilepsy who become pregnant face a difficult choice when it comes to their medication, a new study has found.

According to UK scientists, certain drugs used to control epilepsy during pregnancy may increase the risk of developmental problems in children and more research is needed in this area to ensure women and their doctors are making informed choices.

Around 37,000 Irish people have epilepsy, which is characterised by recurring seizures. These are caused by excess electrical activity in the brain.

Previous research has suggested that some anti-epileptic medications can affect a baby's development in the womb. However for many women with the condition, these drugs are essential to help control seizures while pregnant.

The scientists decided to investigate this further. They analysed data from 28 studies, which measured children's cognitive abilities. The school-aged children had either their IQ (intelligent quotient) or DQ (developmental quotient) measured.

They were split into three groups - those whose mothers had epilepsy and took anti-epileptic medication, those whose mothers had epilepsy but did not take medication and those whose mothers did not have epilepsy.

The study found that the children of women who took sodium valproate, known in Ireland under its brand name Epilim, had lower IQs and DQs than the children of women in the other groups. The higher the dose, the more IQ and DQ appeared to be affected.

These results are not surprising. Last year, Epilepsy Ireland said that the effects of sodium valproate on the foetus have been known ‘for some time'. They advised that women of childbearing age who take this drug should use effective birth control and ‘where possible, consultant neurologists tend to avoid prescribing sodium valproate for such women due to it's known effects'.

"Any woman who becomes pregnant while on sodium valprate should speak to her doctor or specialist nurse for advice but she should not stop taking the medication until advised to do so," it commented.

Meanwhile, the UK study also found that a different epilepsy drug, carbamazepine (known here as Tegretol), did not appear to significantly affect a child's IQ or DQ.

According to the lead scientist, Dr Rebecca Bromley of the University of Manchester, these findings highlight the importance of pre-conception counselling in women with epilepsy.

"Counselling should take account of the fact that many pregnancies are unplanned and cover the risks of anti-epileptic drugs, whilst considering how well they control epileptic seizures," she noted.

The scientists said that patients need to be counselled about the risks and benefits of different medications ‘so that informed decisions can be made'.

"This is particularly important for women with idiopathic generalised epilepsy for whom valproate is the most effective treatment. Some women may choose to initiate valproate as they have no plans to conceive, while others may choose to avoid valproate and try a less effective drug accepting the associated risk of further seizures," they pointed out.

Meanwhile, the scientists noted that data ‘was not available for all anti-epileptic drugs that are in use today and data on newer anti-epileptic drugs was especially scarce'.

"This makes it difficult for women and their doctors to know which medications are safe to use during childbearing years. Future research needs to be carried out in a timelier manner to ensure that when prescribing decisions are being made, the risks are already established. Women should however not stop or make alterations to their medication without first seeking medical advice," they added.

Details of these findings are published in the Cochrane Database of Systematic Reviews 2014.

For more information on epilepsy, see our Epilepsy Clinic here

For more information on pregnancy, see our Pregnancy Clinic here