1. Departments of Obstetrics and Gynecology, University of Utah Health Sciences Center, Salt Lake City, Utah, USA.
2. Departments of Obstetrics and Gynecology, The George Washington University Biostatistics Center, Washington, District of Columbia, USA.
3. Departments of Obstetrics and Gynecology, University of Texas - Southwestern, Dallas, Texas, USA.
4. Departments of Obstetrics and Gynecology, Northwestern University, Chicago, Illinois, USA.
5. Departments of Obstetrics and Gynecology, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland, USA.
6. Departments of Obstetrics and Gynecology, Columbia University, New York, New York, USA.
7. Departments of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina, USA.
8. Departments of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas, USA.
9. Departments of Obstetrics and Gynecology, University of Alabama at Birmingham, Birmingham, Alabama, USA.
10. Departments of Obstetrics and Gynecology, Brown University, Providence, Rhode Island, USA.
11. Departments of Obstetrics and Gynecology, Children’s Memorial Hermann Hospital, The University of Texas Health Science Center at Houston, Houston, Texas, USA.
12. Departments of Obstetrics and Gynecology, The Ohio State University, Columbus, Ohio, USA.
13. Departments of Obstetrics and Gynecology, Case Western Reserve University, Cleveland, Ohio, USA.
14. Departments of Obstetrics and Gynecology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.