1. Department of Pediatrics Emory University School of Medicine/Children's Healthcare of Atlanta Atlanta Georgia USA
2. Division of Reproductive Health National Center for Chronic Disease Prevention and Health Promotion Centers for Disease Control and Prevention Atlanta Georgia USA
3. National Center on Birth Defects and Developmental Disabilities Centers for Disease Control and Prevention Atlanta Georgia USA
4. Office on Smoking and Health National Center for Chronic Disease Prevention and Health Promotion Centers for Disease Control and Prevention Atlanta Georgia USA