1. Department of Obstetrics and Gynecology, Duke University, Durham, North Carolina
2. Department of Obstetrics and Gynecology, Vanderbilt University, Nashville, Tennessee
3. Department of Obstetrics and Gynecology, Wake Forest University, Winston-Salem, North Carolina
4. Department of Obstetrics and Gynecology, Obstetrics/Gynecology and Women's Health Institute, Cleveland Clinic, Cleveland, Ohio