By Maria Bishop
BOSTON, MA -- May 4, 2007 -- The high rate of birth defects in women who take antiepileptic drugs during pregnancy appears to be consistent between large pregnancy registries and a prospective observational investigation at a single center, researchers reported here at the American Academy of Neurology (AAN) 59th Annual Meeting.
Page B. Pennell, MD, associate professor, department of neurology, Emory University School of Medicine, Atlanta, Georgia, has conducted numerous studies on the effects of antiepileptic drugs (AEDs), and said that most multicenter studies provide large numbers of outcomes, but at the expense of detailed, prospective data.
Therefore, Dr. Pennell and colleagues set out to determine pregnancy outcomes for exposure to different AEDs in women with epilepsy who enrolled at Emory University while pregnant or planning a pregnancy beginning in December 2002.
The cohort analysis examined 133 pregnancies in 117 women. There were a total of 11 spontaneous abortions and 1 twin birth, for a total of 123 live infants.
Antiepileptic drugs observed in this study included valproate, lamotrigine, carbamazepine, levetiracetam, phenytoin, oxcarbazepine, gabapentin, and topiramate.
Results demonstrated that high rates of low birth weight (LBW) were found in newborns that were exposed to valproate, carbamazepine, phenytoin, or polytherapy in utero. The researchers noted exceptionally high rates of babies who were small for gestational age (> 15%). This finding held across all drug groups except lamotrigine and gabapentin. Over 15% of infants exposed to valproate, lamotrigine, carbamazepine, and phenytoin required neonatal intensive care unit/special-care nursery admission.
The overall rate of prematurity for all pregnancies on AEDs was similar to the national average at 12.8%, but high rates of prematurity were seen in pregnancies on carbamazepine (28.6%) and on polytherapy (25%). For each drug group, mean estimated gestational ages were greater than 37 weeks and mean APGAR scores were consistently greater than 7, except in the valproate cohort at 1 minute (score of 6.3). The findings with carbamazepine are confounded by paroxetine use and Beckwith-Wiedemann syndrome, the researchers noted.
While findings by individual antiepileptic drug should be interpreted with caution in such a small sample set, the authors warned, these adverse outcomes suggest the potential for future complications, and deserve further study in larger samples, with consideration not only of the drug involved but also the maternal dose and fetal exposure during different stages of pregnancy.
This study was supported by a grant from the National Institutes of Health.
[Presentation title: Pregnancy Outcomes for Women on Antiepileptic Drugs at a Single Site: A Prospective Observational Study. Abstract P06.050]
E-Mail this DGDispatch to a colleague
