1. Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
2. Department of Obstetrics and Gynecology, Christiana Care Health System, Newark, DE
3. Division of Maternal-Fetal Medicine, Department of Obstetrics-Gynecology, School of Medicine, University of California, Irvine, CA
4. Fountain Valley Regional Hospital and Medical Center, Fountain Valley, CA
5. Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, IL
6. Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC
7. Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY
8. Department of Obstetrics and Gynecology, New York Hospital Queens, Queens, NY
9. Department of Obstetrics and Gynecology, Miller Children's Hospital/Long Beach Memorial Medical Center, Long Beach, CA
10. Division of Maternal and Fetal Medicine, Department of Obstetrics and Gynecology, St Peter's University Hospital, New Brunswick, NJ
11. Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, School of Medicine, University of Alabama, Birmingham, AL
12. Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Women and Infants Hospital of Rhode Island, Providence, RI
13. Department of Obstetrics and Gynecology, Tufts Medical Center, Boston, MA