1. HealthPartners Institute Minneapolis Minnesota USA
2. Department of Epidemiology College of Public Health, The University of Iowa Iowa City Iowa USA
3. Stead Family Department of Pediatrics University of Iowa Hospitals and Clinics Iowa City Iowa USA
4. Division of Birth Defects and Infant Disorders National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention Atlanta Georgia USA
5. Center for Birth Defects Research and Prevention Massachusetts Department of Public Health Boston Massachusetts USA
6. Birth Defects Registry New York State Department of Health Albany New York USA
7. Slone Epidemiology Center at Boston University Boston Massachusetts USA
8. Arkansas Center for Birth Defects Research and Prevention Little Rock Arkansas USA
9. Department of Environmental Health Sciences Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences Little Rock Arkansas USA
10. Immunization Safety Office Centers for Disease Control and Prevention Atlanta Georgia USA