Fetal exposure to certain epilepsy drugs is associated with significantly poorer school test results, according to a new UK study conducted by the Neurology Research Group at Swansea University Medical School in Wales.
The findings, published in the Journal of Neurology Neurosurgery & Psychiatry, reveal that seven year-olds who were exposed to the epilepsy drug sodium valproate — or to multiple epilepsy drugs — in the womb achieved significantly poorer school test scores than those in the control group.
Currently, women with epilepsy who need medication to control their seizures are advised to continue taking the drugs during pregnancy because convulsions can harm both mother and baby. However, the researchers recommend that expectant moms be fully informed of the risks of epilepsy treatments, so they can make an educated decision.
Although previous research has suggested that epilepsy drugs, particularly sodium valproate, taken during pregnancy, are associated with neurodevelopmental disorders, few studies have been based on real-life population circumstances (population data).
For the new study, the researchers used routinely-collected healthcare data from the Secure Anonymous Information Linkage (SAIL) databank as well as national school test data (Key Stage 1) to compare the academic performance of seven year-olds in Wales born to mothers with epilepsy.
SAIL contains the anonymous primary health care records of 80 percent of Welsh family doctors, corresponding to around 77 percent of the Welsh population (2.3 million people).
The Key Stage 1 (KS1) test assesses math, language (English/Welsh) and science among seven year-olds, scoring them from levels 1 to 3. Test results were available for 440 children whose mothers had been diagnosed with epilepsy before their pregnancy between the years 2003 and 2008.
Prescription patterns were divided into five categories: treatment with one drug (carbamazepine, lamotrigine or sodium valproate); a combination of several drugs; and no drug treatment. A total of 20 of the 39 moms (54 percent) prescribed several drugs were taking sodium valproate, but there were 15 different drug combinations in all.
The findings reveal that children born to mothers who had been prescribed carbamazepine or lamotrigine, or nothing, performed just as well as those born to moms of the same age and deprivation level, but without epilepsy (control group).
However, children whose mothers had been prescribed sodium valproate during their pregnancy performed 10.5 – 13 percent worse on all KSI tests compared to those in the control group.
Furthermore, children born to mothers who had been prescribed a combination of epilepsy drugs achieved the worst results in the study with scores being 19-22 percent lower. The findings remained after factoring in smoking and children with epilepsy.
“Women with epilepsy should be informed of this risk and alternative treatment regimens should be discussed before their pregnancy with a physician that specialises in epilepsy,” said Dr. Owen Pickrell, leader of the SAIL neurology team.
The researchers note that they were unable to account for certain potentially influential factors, such as the mothers’ IQ, weight or alcohol consumption; the doses of epilepsy drugs prescribed; or intake of folic acid around conception. But the findings match up with those of other independent studies, they point out.
“While this study highlights the risk of cognitive effects in the children of mothers prescribed sodium valproate or multiple [anti-epilepsy drugs], it is important to acknowledge that some epilepsies are difficult to manage without these treatment regimens,” said Professor Mark Rees, Professor of Neurology and Molecular Neuroscience Research.
Source: Swansea University