Women with epilepsy should be warned upon diagnosis that some treatments for the condition may have adverse effects on the neurodevelopment of unborn babies.
These women should also be told about alternative treatment options so that they are well informed before they become pregnant, says Rebecca Bromley from the Institute of Human Development at the University of Manchester, the lead researcher behind a drug review published on 29 October 2014 in the Cochrane Database of Systematic Reviews
Many pregnancies are unplanned and women should be counselled on the balance between the neurodevelopment of an unborn child and the needs of the mother to control seizures, Bromley says.
The researchers looked at the results of 28 studies and the neurodevelopment of children born to women with epilepsy and their prenatal exposure to commonly prescribed anti-epileptic drugs.
They measured children’s global cognitive ability using intelligence quotient (IQ) for school aged children and developmental quotient (DQ) for younger children. They looked at DQ and IQ scores in the children of three groups – women with epilepsy who took anti-epilepsy medication, those with epilepsy who did not take drugs and women who did not have epilepsy.
The researchers found that the children of women who took sodium valproate had lower DQs and IQs than the children of women in the other two groups. Higher doses of the drug were linked to larger effects on IQ or DQ.
But they advise that most women with epilepsy should continue their treatment when pregnant because uncontrolled seizures also carry a maternal risk.
The researchers also discovered that the anti-epileptic drug carbamazepine did not appear to have any significant effects on DQ or IQ. Although younger children born to women who took carbamazepine did have lower DQs, the researchers say this was due to “random variation” between the results of studies.
They found that the children of women who took valproate had lower IQs than children exposed to carbamazepine or lamotrigine in the womb. They also had lower DQs and IQs than children born to women who took phenytoin. There were no differences between the IQs of children exposed to either carbamazepine, phenytoin or lamotrigine, they found.
“The most important finding is the reduction in IQ in the sodium valproate exposed group, which are sufficient to affect education and occupational outcomes in later life,” the researchers conclude.
Kathy Bairstow, senior advice and information services officer for the patient charity Epilepsy Action, said the findings confirmed what women already know. “Pregnancy can be a huge issue for women with epilepsy and can be quite difficult in cases where sodium valproate is the only drug that controls your seizures with the fewest side effects,” she says. “Women will be guided by their epilepsy specialist or nurse and it’s really important that they get pre-conception counselling.”