1. Department of Obstetrics and Gynecology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
2. Department of Obstetrics, Gynecology and Reproductive Services, Yale University School of Medicine, New Haven, Connecticut
3. Center for Clinical Epidemiology and Biostatics, Perelman School of Medicine, University of Pennsylvania, Pennsylvania
4. Department of Laboratory Medicine, University of Washington, Seattle, Washington
5. Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
6. Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan
7. Fertility and Infertility Branch, Eunice Kenney Shriver National Institute of Child Health and Human Development, Rockville, Maryland
8. Department of Obstetrics and Gynecology, University of Colorado, Aurora, Colorado
9. Department of Biostatistics, Yale University School of Public Health, New Haven, Connecticut
10. Department of Obstetrics and Gynecology, Georgia Regents University, Augusta, Georgia
11. Department of Obstetrics and Gynecology, Pennsylvania State University Hershey, Hershey, Pennsylvania