State-based surveillance programs monitor the prevalence of certain birth defects through various methods, including passive hospital-based reporting and active medical-record abstraction.6 These data are used for prevention, education,
policy, and health-care planning.7 However,
most state-based surveillance programs were established in recent years and only monitor certain types of defects; therefore, population-based estimates of the overall prevalence of all defects and data on long-term trends are lacking in the United States. MACDP, established in 1967
by CDC, Emory University, and the Georgia Mental Health Institute,
monitors the prevalence of all major structural or genetic defects at the time of delivery among live births, stillbirths, and pregnancies electively terminated after prenatal diagnosis of defects at ≥20
weeks' gestation in the five central counties of metropolitan Atlanta.5 MACDP defines major structural or genetic birth defects as conditions that (1) result from a malformation, deformation,
or disruption in one or more parts of the body, a chromosomal abnormality,
or a known clinical syndrome; (2) are present at birth; and (3) have a serious, adverse effect on health, development, or functional ability.