Modest difference: prenatal phenobarbital tied to lower cognitive ability.(Obstetrics)

VANCOUVER, B.C. -- Maternal use of phenobarbital in pregnancy has been linked with major malformations in children, but even in the absence of such malformations, those who were exposed to the drug in utero show mild reductions in general mental ability, Jane Adams, Ph.D., said during the annual meeting of the Teratology Society.

Rates of major malformations, including heart defects and cleft lip and palate, have been documented to be three to four times higher in those who were exposed to phenobarbital in the prental period.

Minor malformations include midface and digital hypoplasia, according to Dr. Adams, who is a professor of psychology at the University of Massachusetts. Boston.

Studies also have shown mild reductions in cognitive ability, with language processing as an area of specific weakness in men.

Research by Dr. Adams has shown further evidence of deficits in general mental ability as well as verbal performance.

In ongoing research testing in exposed participants, Dr. Adams said that she found scores on the general, verbal, and nonverbal indices of the Wechsler Intelligence Scale for Children-III test to be 1-14 points lower on all three indices among exposed children, compared with nonexposed controls.

Verbal scores often represent the greatest area of weakness, and while the effect from phenobarbital exposure is "fairly modest," the levels are not necessarily such that ...