Updated National Birth Prevalence Estimates for Selected Birth Defects in the United States, 2004–2006 Samantha E. Parker, 1,2 Cara T. Mai, 1 * Mark A. Canfield, 3 Russel Rickard, 4 Ying Wang, 5 Robert E. Meyer, 6 Patrick Anderson, 7 Craig A. Mason, 8 Julianne S. Collins, 9 Russell S. Kirby, 10 and Adolfo Correa 1 for the National Birth Defects Prevention Network 1 National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia 2 Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee 3 Birth Defects Epidemiology and Surveillance Branch, Texas Department of State Health Services, Austin, Texas 4 Colorado Department of Public Health and Environment, Denver, Colorado 5 New York State Department of Health, Troy, New York 6 North Carolina Birth Defects Monitoring Program, State Center for Health Statistics, Raleigh, North Carolina 7 California Department of Public Health, Sacramento, California 8 University of Maine, Orono, Maine 9 J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, South Carolina 10 University of South Florida, Tampa, Florida Received 1 June 2010; Revised 9 July 2010; Accepted 29 July 2010 BACKGROUND: The National Birth Defects Prevention Network collects state-specific birth defects surveil- lance data for annual publication of prevalence estimates and collaborative research projects. In 2006, data for 21 birth defects from 1999 through 2001 were presented as national birth prevalence estimates. The pur- pose of this report was to update these estimates using data from 2004 through 2006. METHODS: Popula- tion-based data from 11 active case-finding programs, 6 passive case-finding programs with case confirma- tion, and 7 passive programs without case confirmation were used in this analysis. Pooled birth prevalence estimates for 21 birth defects, stratified by case ascertainment approach, were calculated. National prevalence estimates, adjusted for maternal race/ethnicity and maternal age (trisomy 13, trisomy 18, and Down syn- drome only) were determined using data from 14 programs. The impact of pregnancy outcomes on preva- lence estimates was also assessed for five specific defects. RESULTS: National birth defects prevalence esti- mates ranged from 0.72 per 10,000 live births for common truncus to 14.47 per 10,000 live births for Down syndrome. Stratification by type of surveillance system showed that active programs had a higher prevalence of anencephaly, anophthalmia/microphthalmia, cleft lip with or without cleft palate, reduction defect of upper limbs, and trisomy 18. The birth prevalence of anencephaly, trisomy 13, and trisomy 18 also varied substantially with inclusion of elective terminations. CONCLUSION: Accurate and timely national estimates of the prevalence of birth defects are needed for monitoring trends, assessing prevention efforts, determining service planning, and understanding the burden of disease due to birth defects in the United States. Birth Defects Research (Part A) 88:1008–1016, 2010. Ó 2010 Wiley-Liss, Inc. Key words: birth defects; surveillance; prevalence; national estimates; United States INTRODUCTION Major birth defects (i.e., structural malformations with a significant impact on the health and development of a child) remain an important public health issue because they are a leading cause of infant mortality and lifelong disabilities; in addition, they substantially impact health care costs. Birth defects contributed to more than 5500 The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Con- trol and Prevention. *Correspondence to: Cara Mai, MPH, CDC/NCBDDD, 1600 Clifton Rd, MS E- 86, Atlanta, GA 30333. E-mail: cmai@cdc.gov Published online 28 September 2010 in Wiley Online Library (wileyonlinelibrary. com). DOI: 10.1002/bdra.20735 Birth Defects Research (Part A): Clinical and Molecular Teratology 88:1008À1016 (2010) Ó 2010 Wiley-Liss, Inc. Birth Defects Research (Part A) 88:1008À1016 (2010)