1. Department of Obstetrics and Gynecology, The Ohio State University College of Medicine, Columbus, OH
2. George Washington University Biostatistics Center, Washington, DC
3. Department of Obstetrics and Gynecology, University of Utah Health Sciences Center, Salt Lake City, UT
4. Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX
5. Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD
6. Department of Obstetrics and Gynecology, Columbia University, New York, NY
7. Department of Obstetrics and Gynecology, Brown University, Providence, RI
8. Department of Obstetrics and Gynecology, University of Alabama at Birmingham, Birmingham, AL
9. Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill, Chapel Hill, NC
10. Department of Obstetrics and Gynecology, Case Western Reserve University–MetroHealth Medical Center, Cleveland, OH
11. Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX
12. Department of Obstetrics and Gynecology, Northwestern University, Chicago, IL
13. Department of Obstetrics and Gynecology, University of Texas Health Science Center at Houston–Children’s Memorial Hermann Hospital, Houston, TX
14. Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC