But the Harvard Medical School-led study found this increases to 12.3 in every 1,000 for those mothers on high doses of topiramate, defined as 200mg.
Researchers found the risk is 12 times above normal for expectant mothers given the drug topiramate, branded as Topamax.
Pregnant women who take a widely-prescribed epilepsy drug are more likely to have a child with a cleft lip, a major study concludes.
It is unsure how many women take the drug, but there are 2,500 epileptic women that give birth every year in the UK. The figure is 10 times higher in the US.
Researchers found the risk is 12 times above normal for expectant mothers given the drug topiramate, branded as Topamax
The researchers, which included a team from Brigham and Women’s Hospital, have now called for doctors to avoid prescribing high doses of the drug unless the ‘benefits clearly outweigh the risks’.
How many people take the drug?
Epilepsy UK states that adults, including pregnant women, should take between 100-200mg of topamirate to combat seizures.
Topiramate is also given to treat migraines, bipolar disorder and even weight loss – but scientists warned the risk is much lower for those women.
Epileptics are given much higher doses of the drug to control their seizures, said Dr Sonia Hernandez-Diaz, lead author of the US Government-funded study.
What do the researchers say?
She said: ‘The best course may be to avoid prescribing high doses of topiramate to women of childbearing age unless the benefits clearly outweigh the risks.
‘Our results suggest women with epilepsy on topiramate have the highest relative risk of giving birth to a baby with cleft lip or cleft palate.’
Dr Hernandez-Diaz revealed this was ‘likely due to the higher doses of topiramate when used for controlling seizures.’
ANOTHER SCANDAL-HIT EPILEPSY DRUG
Thousands of angry mothers believe they were deceived about the risks of taking scandal-hit epilepsy pills during pregnancy, it was reported in September.
Nearly 20,000 babies have been born with disabilities since sodium valproate was introduced in the 1970s, figures show.
The drug can cause severe birth defects, including spina bifida, where the spinal cord doesn’t form correctly, and heart and genital defects.
Babies exposed to the drug in pregnancy have a 30 to 40 per cent risk of serious developmental disorders and an 11 per cent risk of congenital malformations.
Sodium valproate is only recommend during pregnancy if there is no better option to control symptoms of their epileptic seizures.
But scores of women say they weren’t warned of the extent of the risk. They have since provided evidence to a European drug regulator.
The study, published in Neurology, follows the widely-publicised dangers of another common epilepsy drug given to pregnant women.
In the wake of another scandal
Figures estimate 20,000 British children have been severely harmed because their mothers took the drug sodium valproate during pregnancy.
But campaigners have argued the risks, which were known by its manufacturers and regulators, were kept from patients for more than 40 years.
The new study, which used data from between 2000 and 2010, adds to the growing bill of dangerous drugs for pregnant women who are epileptic.
Evidence already shows women taking topiramate during early pregnancy increases the risk of having a baby with a cleft lip five-fold.
But the new experiment was the first to delve into the dangers of women taking the drug at a lower dose for non-seizure related conditions.
How was the study carried out?
Researchers examined the risk of oral clefs – including cleft palate or cleft lip – using data from Medicaid.
Subjects were split into three groups, depending on what drug, if any, their mother was given during her pregnancy.
They found infants exposed to low doses of topiramate, defined as 100mg each day, faced a higher chance of being born with a cleft.
Out of every 1,000 births, 2.1 children in this group were born with a cleft – double the standard rate, according to figures.