1. Warren Alpert Medical School of Brown University, Providence, RI, USA
2. Department of Obstetrics and Gynecology, Eastern VA Medical College, Norfolk, VA, USA
3. Department of Obstetrics & Gynecology, University of UT School of Medicine, Salt Lake City, UT, USA
4. Department of Obstetrics & Gynecology, Columbia University School of Medicine, NY, NY, USA
5. Department of Obstetrics & Gynecology, University of Virginia, Charlottesville, VA, USA
6. Department of Pathology, Women and Infants Hospital of Rhode Island, Providence, RI, USA