1. Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, Virginia
2. Department of Obstetrics and Gynecology, College of Physicians and Surgeons, Columbia University, New York
3. Department of Obstetrics and Gynecology, Aurora Sinai Medical Center, Milwaukee, Wisconsin
4. Department of Obstetrics and Gynecology, Winthrop University Hospital, Mineola, New York
5. Center for Urban Population Health, Milwaukee, Wisconsin