1. Department of Medicine, St. Michael’s Hospital, University of Toronto, Toronto, Ontario, Canada
2. Department of Obstetrics and Gynaecology, St. Michael’s Hospital, University of Toronto, Toronto, Ontario, Canada
3. Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada
4. Maternal, Child and Youth Health Unit, Public Health Agency of Canada, Ottawa, Ontario, Canada
5. Department of Medicine, McGill University, Montreal, Quebec, Canada
6. Department of Epidemiology, McGill University, Montreal, Quebec, Canada
7. Research Institute, McGill University Health Centre, Montreal, Quebec, Canada
8. Department of Obstetrics and Gynaecology, School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada