Teratogenicity of anticonvulsant drugs. III: Radiographic hand analysis of children exposed in utero to diphenylhydantoin.

As part of a prospective study of the teratogenicity of anticonvulsant drugs, hand radiographs were obtained on 51 children born to epileptic mothers. The phalanges and metacarpals were measured and a diagnosis of distal digital hypoplasia (DDH) was made if the distal phalangeal to other digital bone ratio was more than 2 SD below the mean for age in at least two of the digits. By these criteria, roughly 30% of infants exposed to diphenylhydantoin in utero demonstrate DDH; this was in close agreement with the clinical diagnosis of DDH. The data suggest that there is no familial tendency to the expression of this teratogenicity, there is no sex influence, there is no difference between exposure to diphenylhydantoin alone and diphenylhydantoin in combination with other anticonvulsants, and that the digital changes occur most often in the absence of other sequelae of in utero exposure to diphenylhydantoin.