1. Department of Obstetrics and Gynecology and University of Toronto, Toronto, Canada.
2. Department of Obstetrics and Gynecology, St. Michael's Hospital, Toronto, Canada.
3. Department of Family and Community Medicine, University of Toronto, Toronto, Canada.
4. Department of Evaluative Clinical Sciences and Sunnybrook Health Sciences Centre, Toronto, Canada.
5. Department of Health Sciences, Western University, London, Canada.
6. Department of Obstetrics and Gynecology, Sunnybrook Health Sciences Centre, Toronto, Canada.