1. Department of Epidemiology Gillings School of Global Public Health, University of North Carolina at Chapel Hill Chapel Hill North Carolina USA
2. Birth Defects Registry New York State Department of Health Albany New York USA
3. Division of Medical Genetics, Department of Pediatrics University of Utah School of Medicine Salt Lake City Utah USA
4. College of Public Health The University of Iowa Iowa City Iowa USA
5. Massachusetts Center for Birth Defects Research and Prevention Massachusetts Department of Public Health Boston Massachusetts USA