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Impact of prenatal exposure to anticonvulsants appears small.

TUCSON, ARIZ. -- The use of carbamazepine, phenytoin, or phenobarbital as monotherapy by pregnant women was not associated with significant deficits in full-scale IQ in their offspring, a small study showed.

However, these data counter previous reports of lowered intellectual ability in children born to mothers who took anticonvulsant medications during pregnancy, Dr. Kenneth Lyons Jones said at the annual meeting of the Teratology Society.

"The results, then, should be considered in conjunction with previous studies when evaluating the risks associated with use of these medications during pregnancy," cautioned Dr. Jones, chief of the division of dysmorphology and teratology in the department of pediatrics at the University of California, San Diego.

Despite the documented increased risk for certain major malformations following prenatal exposure to anticonvulsants, he said that "substantial controversy" exists about their impact on neurobehavioral outcomes.

"Compounding these concerns is the fact that in the United States, between 7.6 and 12.7 million women have epilepsy, and 95% of them are being treated with anticonvulsant drugs," Dr. Jones said. "In addition, 1 in every 200 pregnant women in the general population requires antiepileptic medication during their pregnancy."

Dr. Jones and his associates studied 82 children aged 4-14 years whose mothers were taking anticonvulsant monotherapy and contacted the California Teratogen Information Service (CTIS) during their pregnancies. Of the 82 children, 30 were exposed to carbamazepine, 23 were exposed to phenytoin, and 29 were exposed to phenobarbital.

The researchers randomly selected 50 matched controls who were born to women who contacted CTIS because of an exposure not deemed to be teratogenic.

All children underwent neuropsychiatric testing that included a measure of full-scale IQ (FSIQ). Testing was conducted at the Center for Behavioral Teratology at San Diego State University or in a location near the child's home.

Dr. Jones reported that 26% of children exposed to phenytoin were rated as affected with features of the anticonvulsant facies based on ratings of minor malformations, compared with 24% of those exposed to phenobarbital and only 3% of those exposed to carbamazepine. None of the children in the control group was considered affected.

In terms of the FSIQ, there were no statistically significant differences in scores between exposed children and controls, nor did any of the exposed children differ from each other, even after the researchers controlled for age and socioeconomic status.

The mean FSIQ scores were as follows: 106.3 for those exposed to carbamazepine; 105.6 for those exposed to phenytoin; 107.6 for those exposed to phenobarbital, and 108.6 for nonexposed controls.

Dr. Jones also noted that there were no differences in the number of children per group who had FSIQ scores below 85, which is the cutoff score for average IQ. Further, there were no differences in the mean FSIQ scores between children who were rated as having features of the anticonvulsant facies and those who were mildly affected (such as having nail hypoplasia) or unaffected by exposure.

"These results suggest that when other factors are excluded, such as polytherapy, or controlled for, such as socioeconomic status, prenatal exposures to these medications were not associated with significant deficits in FSIQ," Dr. Jones said.

He acknowledged certain limitations of the study, including the fact that the population studied was homogeneous, the sample size was small, and there was potential for selection bias.


San Diego Bureau
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Title Annotation:Across Specialties
Author:Brunk, Doug
Publication:Clinical Psychiatry News
Geographic Code:1U8AZ
Date:Sep 1, 2006
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