[1] Inst Natl Sante Publ Quebec, Montreal, PQ, Canada
[2] HealthPartners Inst, Pregnancy & Child Hlth Res Ctr, Bloomington, MN 55420 USA
[3] McGill Univ, Dept Epidemiol Biostat & Occupat Hlth, Montreal, PQ, Canada
[4] Univ British Columbia, Dept Obstet & Gynaecol, Vancouver, BC, Canada
[5] Univ British Columbia, BC Childrens & Womens Hosp, Vancouver, BC, Canada
[6] Univ Toronto, Dept Med, Toronto, ON, Canada
[7] Univ Toronto, Inst Hlth Policy & Evaluat, Toronto, ON, Canada
[8] Univ Ottawa, Dept Obstet & Gynecol, Ottawa, ON, Canada
[9] McGill Univ, Dept Med, Hlth Ctr, Montreal, PQ, Canada
[10] McGill Univ, Ctr Outcomes Res & Evaluat, Res Inst, Hlth Ctr, Montreal, PQ, Canada