Two drugs used to combat epileptic seizures – and prescribed to patients with migraine, pain and bipolar disorder – are associated with increased risk of birth defects, new research suggests.
For the study, researchers used data from the French national health system to identify pregnancies that resulted in live birth between January 2011 and March 2015. Among the 1,886,825 pregnancies, the researchers sought after mother's use of 10 anti-seizure symptoms before and after conception and sought 23 birth rate in the children born to these women.
A total of 8,794 women had been prescribed a single anti-epileptic drug, the researchers found.
Women prescribed valproic acid (10.4% of the group of pregnant women who prescribed anti-epileptic medicine) had a 19-fold greater risk of having a baby with spina bifida compared to women who did not take an epilepsy drug. Among the 913 women who prescribed valproic acid, six children (0.66%) had spina bifida, compared to 616 children (0.03%) born to women who did not take an epilepsy. Valproic acid also increased the risk of seven other birth defects, including cleft palate and four types of heart failure.
Women prescribed topiramate (5.9%) had a seven-fold greater risk of having a baby with cleft lip (with or without cleft palate), the study indicates. Among the 517 women who prescribed topiramate, three infants (0.60%) had cleavage lip, compared to 1,637 children (0.09%) born to women who did not take an epilepsy drug.
No increased risks of birth defects were associated with lamotrigine, levetiracetam, carbamazepine, oxcarbazepine and gabapentin.
The researchers received weak signals that linked clonazepam to a higher risk of microcephaly (a small main area associated with lower IQ), whereas individually, phenobarbital and pregabalin were associated with higher risks for different types of heart failure. These compounds were founded on very few children and therefore cannot be considered statistically significant, they said.
Dr David Ficker, chair of the Epilepsy Foundation's Professional Advisory Board, said the new study "confirms other major studies that have found similar results. It reinforces the risks associated with these two drugs."
There are different levels of care for patients with epilepsy, with some treated by their primary care providers, others treated by neurologists and still others treated by epilepsy specialists – neurologists with special training in the disease.
"We are well aware of the risks of valproic acid during pregnancy." I believe that in the neurological community, too, "says Ficker, who is also a professor of neurology at the University of Cincinnati Gardner Neuroscience Institute. But the primary care organization may not recognize potential safety risks, he said.
"I also know that there are some women with difficulty controlling epilepsy that valproic acid can be the only medicine that can be effective for them. All these different drugs have different ways of working in the brain, and they aren't necessarily entirely interchangeable."
"Fortunately, for many women there are alternative drugs that can be used that have a better safety profile during pregnancy," he said.
Still, it is important to control seizures because they pose dangers – for example, falling, miscarriage, impaired oxygen to the fetus and fetal distress – to a developing baby as well, he said.
Ultimately, Ficker warns women with epilepsy who are of childbearing age or pregnant, "do not stop the medicine without talking to your treating doctor."
Interaction with birth control
American Epilepsy Society President, Dr. Page Pennell, agreed that the results of the studies are not new, as most of these relationships between anti-epileptic use during pregnancy and birth defects were known from "many studies" of populations in North America, Australia and other European countries.
However, previous studies have shown evidence of additional negative compounds, Pennell wrote, who was not involved in the new research, in an email: "Most notably used prodrug use during pregnancy has been associated with higher risk of lower IQ, autism and autism spectrum disorder and need for Special education in children exposed during pregnancy. Topiramate has also been associated with an increased risk of low birth weight. "
Although the evidence is not essential, she also highlighted the "relatively new result" of the study of an association using clonazepam and microcephaly and pregabalin and a heart failure. Of the total women prescribed anti-epileptic drugs, 11.1% had received a script for clonazepam and 19.0% for pregabalin, the study found.
The new research also suggests that neurologists are proactive to ensure that patients of childbearing age take extra folic acid, which "has been associated with lowering the risk of neurodevelopmental disorders, including autism in women of epilepsy women," says Pennell.
Like Ficker, she recommends counseling to young women prescribed anti-epileptic drugs, because "over 50% of pregnancies are unplanned in the United States" and women taking anti-epileptic drugs "still have a high level of unplanned pregnancy," despite the known risks.
But not all of these pregnancies are due to a lack of performance. Carbamazepine, she explained, and some of the other drugs to control seizures may interact with birth control and "may increase the rate of unplanned pregnancies".
Pennell stated that "a planned pregnancy allows the caregiver and the woman to decide the best plan for her individually … to lower the fetal risk while keeping her fit under optimal control".