Temporal trends in the incidence of birth defects -- United States.

Through CDC's Birth Defects Monitoring Program (BDMP), a total of 161 categories of birth defects are analyzed quarterly to determine increases or other unusual trends. Sixteen of these malformations have been selected for review in this report because they occur in sufficient numbers to provide relatively stable rates, the coding categories for them are relatively homogeneous, and they represent defects of different organ systems.