Pregnant women taking common epilepsy drugs have a higher chance of delivering a baby with spina bifida, experts have confirmed.
Previous studies have shown a link between the condition and the medicines valproic acid and carbamazepine, which are used to treat epilepsy and some mental health problems, such as bipolar disorder and schizophrenia.
Now experts writing in the British Medical Journal (BMJ) have confirmed today the link in a systematic review involving more than 3.8 million births.
The researchers, led by Professor Lolkje de Jong-van den Berg from the University of Groningen in the Netherlands, looked for evidence of major malformations linked with carbamazepine use in the first three months of pregnancy. Spina bifida was the only one noted but was 2.6 times more likely in babies born to women who had taken carbamazepine compared with those not taking any anti-epileptic drug.
However, the experts did say it carried smaller risks than valproic acid, which was also included in some of the studies.
In conclusion, the experts said: “Although most anti-epileptic drugs taken during pregnancy significantly increase the risk for one or more specific fetal malformations, the occurrence of these malformations is nevertheless rare.
“Most exposed pregnancies result in a baby without malformation.
“The best option regarding anti-epileptic drug treatment can be chosen only on an individual basis by the woman and neurologist before pregnancy, weighing the benefits of epilepsy control against the risk.”
Spina bifida means ‘split spine'. There are 33 vertebrae in the spine.
If one or more of these don't form properly in early pregnancy, the nerves in the spine may be unprotected, which can then lead to damage of the central nervous system.
This damage may cause mobility difficulties, bladder and bowel problems and, in more severe cases, paralysis below the affected part of the spine.
Disruption of the nervous system depends on how high up the spine the problem lies and how well the spinal cord below the defect works.
If the defect is minor, usually no treatment is necessary.
But if the defect is more serious, then surgery to repair it is often performed.