1. Massachusetts Department of Public Health, Massachusetts Center for Birth Defects Research and Prevention, Boston, MA, USA
2. Department of Epidemiology, College of Public Health, The University of Iowa, Iowa City, IA, USA
3. New York State Department of Health, Congenital Malformations Registry, Albany, NY, USA
4. March of Dimes Foundation, California Research Division, Oakland, California, USA
5. Department of Pediatrics, Stanford University, Stanford, California, USA