Temporal trends in the prevalence of congenital malformations at birth based on the birth defects monitoring program, United States, 1979-1987.

The Birth Defects Monitoring Program (BDMP) is a national program that monitors congenital malformations by using hospital discharge data concerning newborns. BDMP data for 38 selected malformations were examined for temporal trends. The prevalence at birth of these malformations for the two periods 1979-1980 and 1986-1987 was compared and then grouped into three time-trend categories: increasing greater than or equal to 2% annually, decreasing greater than or equal to 2% annually, and remaining stable. Results showed that 29 malformations had increasing trends, two had decreasing trends and seven remained stable. Follow-up studies are needed to evaluate whether these trends are real or due to improved ascertainment of the respective malformations.