1. Columbia University Vagelos College of Physicians & Surgeons New York New York USA
2. Department of Pediatrics Columbia University Irving Medical Center New York New York USA
3. George Washington University Biostatistics Center Washington District of Columbia USA
4. Department of Obstetrics and Gynecology Columbia University Irving Medical Center New York New York USA
5. Department of Obstetrics & Gynecology and Molecular & Human Genetics Baylor College of Medicine, and Texas Children's Hospital Houston Texas USA
6. Department of Obstetrics & Gynecology University of North Carolina Chapel Hill Chapel Hill North Carolina USA
7. Department of Obstetrics & Gynecology Oregon Health & Science University Portland Oregon USA
8. Department of Medicine Columbia University Irving Medical Center New York New York USA