[1] McGill Univ, Dept Epidemil Biostat & Occupat Hlth, Montreal, PQ, Canada
[2] Jewish Gen Hosp, Lady Davis Inst, Ctr Clin Epidemiol, Montreal, PQ, Canada
[3] McGill Univ, Dept Med, Montreal, PQ, Canada
[4] Univ British Columbia, Dept Obstet & Gynaecol, Fac Med, Vancouver, BC, Canada
[5] Queens Univ, Sch Med, Dept Obstet & Gynaecol, Kingston, ON, Canada
[6] McGill Univ, Schulich Lib Sci & Engn, Montreal, PQ, Canada
[7] Univ Toronto, Dept Med, Toronto, ON, Canada
[8] Univ Toronto, Inst Hlth Policy Management & Evaluat, Toronto, ON, Canada
[9] Univ Calgary, Cumming Sch Med, Dept Med, Calgary, AB, Canada
[10] McGill Univ, Hlth Ctr, Res Inst, Montreal, PQ, Canada
[11] McGill Univ, Dept Pediat, Montreal, PQ, Canada