1. Department of Obstetrics and Gynaecology, University of British Columbia, Vancouver, Canada
2. The School of Population and Public Health, University of British Columbia, Vancouver, Canada
3. Department of Family Practice, University of British Columbia, Vancouver, Canada
4. Department of Family and Community Medicine, University of Toronto, Toronto, ON, Canada
5. Department of Obstetrics and Gynaecology, Laval University, Quebec City, QC, Canada
6. Department of Public Health, Environments and Society, Faculty of Public Health & Policy, London School of Hygiene & Tropical Medicine, London, UK