Is Bendectin a teratogen?

We studied the first-trimester exposure to Bendectin for several major categories of birth defects among infants ascertained through the Metropolitan Atlanta Congenital Defects Program from 1968 to 1978. No associations were found between any of these defect categories and Bendectin exposure. An association, however, was found for the amniotic bands cases--a subgroup of limb reductions. We stratified our data to reflect the 1976 change in formulation when one of the three ingredients was removed. An association was found between esophageal atresia and the three-ingredient product and another between encephalocele and the two ingredient product. These statistical associations do not establish a causal relationship between Bendectin and the birth defects we studied. Furthermore, even if the associations are causal, the implied risk is extremely low, approximately one in 1,000 births.