1. From the National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Ga (S.M.G., A.C.); Department of Epidemiology and Biostatistics, College of Public Health, University of South Florida, Tampa (J.L.S., W.N.N.); and Division of Cardiology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas (D.E.F.).