1. Department of Obstetrics and Gynecology, MetroHealth Medical Center, Cleveland, Ohio.
2. Center for Health Equity Research and Promotion, VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania.
3. University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
4. Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.
5. Health Services Research and Development, VA Puget Sound Health Care System, Seattle, Washington.
6. Department of Obstetrics & Gynecology, University of Washington School of Medicine, Seattle, Washington.
7. Center for Research on Health Care, University of Pittsburgh, Pittsburgh, Pennsylvania.