Study Finds New Fetal Risks Associated with Antiepileptic DrugsSep 26, 2013
New research reveals that antiepileptic drugs—AEDs—contain more risks to developing fetuses than are mentioned on the drug’s label. AEDs include the brands Tegretol, Carbatrol, Equetro, Epitol, Lomotrigine, and Depakote. The active ingredient in Depakote is valproate.
Using a population-based registry study in Denmark, the researchers discovered that AEDs are tied to significantly more risks. The study reveals that low birth weight, preterm birth, and smaller-than-normal head circumference are the key additional risks faced by epileptic pregnant women who require medication, said Demet Kilic, MD, of Aarhus University Hospital in Aarhus, Denmark, according to MedPageToday.
Out of some 1 million pregnancies in Denmark from 1997 to 2008, 2,928 involved births in which the mothers’ medical records indicated that they had used AEDs during their pregnancy, Dr. Kilic told attendees at the World Congress of Neurology, MedPageToday reported. After adjusting for so-called “confounders,” the research revealed the following adverse birth outcomes, which the team concluded were significantly more common in these AED births when compared to births in which AEDs were not involved:
- Gestational age: Lower by 0.92 days
- Birth weight: Lower by 31.96 grams
- Head circumference: Smaller by 0.07 centimeters
Dr. Kilic also said that the relative risk for preterm birth—sooner than 37 weeks of gestation—was 1.51 in the AED-associated pregnancies, while the relative risk for a baby being born undersized for his/her gestational age was 1.21, according to MedPageToday.
Similar risks have been seen in animal studies; however, prescribing information for approved AEDs has only focused on birth defects. For example, notes MedPageToday, the labeling for Tegretol-XR (carbamazepine), which carries a "D" rating for pregnancy risks over positive evidence of fetal risk, only mentions "craniofacial defects, cardiovascular malformations, hypospadias, and anomalies involving various body systems" based on epidemiological data. The potential for low birth weight or preterm birth are not indicated. The Danish study, explained Dr. Kilic, was meant to fill that research gap.
We recently wrote that babies born to mothers exposed to AEDs during pregnancy were likely to have abnormal scores on motor development and autism traits testing, according to another study. These findings, MedPageToday previously noted, add to prior research, tying epilepsy drugs to congenital defects, concluded Gyri Veiby, MD, of Haukeland University Hospital in Bergen, Norway, and co-authors in an article published online in Epilepsia. “Exposures to valproate, lamotrigine, carbamazepine, or multiple antiepileptic drugs were associated with adverse outcomes within different developmental domains,” the authors concluded.
Another Danish study previously revealed additional evidence that fetal exposure to Depakote, specifically its active ingredient, valproate, increases threefold a baby’s risk of developing autism spectrum disorders (ASD). Depakote, approved for the prevention of migraines, treating acute manic episodes in bipolar patients, and halting seizures in adults and children, has been associated with birth defects when taken by pregnant women. In fact, 26 women previously filed lawsuits claiming that the manufacturers of Depakote illegally marketed the medication for off-label uses and neglected to warn of the drug’s side effects. Each woman claimed she was prescribed and took Depakote just prior to becoming pregnant or during the first trimester of her pregnancy and that the drug caused her to give birth to a child with a wide array of severe, sometimes life-threatening, birth defects.