1. Department of Obstetrics and Gynecology University of Calgary Calgary Alberta Canada
2. Department of Medicine University of Calgary Calgary Alberta Canada
3. Department of Community Health Sciences University of Calgary Calgary Alberta Canada
4. Department of Obstetrics and Gynecology University of British Columbia Vancouver British Columbia Canada
5. School of Population and Public Health University of British Columbia Vancouver British Columbia Canada
6. Department of Obstetrics and Gynecology King Saud University Riyadh Saudi Arabia