1. Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
2. Department of Pediatrics, University of Rochester Medical Center, Rochester, New York
3. Statistics and Epidemiology Unit RTI International, Research Triangle Park, North Carolina
4. National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia
5. NANEA Department of Epidemiology Institute of Public Health, University of Aarhus, Aarhus, Denmark; Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia
6. Neonatal Research Network, Pregnancy and Perinatology Branch, Center for Developmental Biology and Perinatal Medicine, Bethesda, Maryland