[1] McMaster Univ, Dept Obstet & Gynecol, 1280 Main St West,HSC 4H24-B, Hamilton, ON, Canada
[2] McMaster Univ, Dept Hlth Res Methods Evidence & Impact, Hamilton, ON, Canada
[3] Univ Toronto, Mt Sinai Hosp, Dept Obstet & Gynecol, Div Maternal Fetal Med, Toronto, ON, Canada
[4] Univ Toronto, Lunenfeld Tanenbaum Res Inst, Mt Sinai Hosp, Toronto, ON, Canada
[5] McGill Univ, Hlth Ctr, Dept Med, Div Gen Internal Med, Montreal, PQ, Canada
[6] McGill Univ, Hlth Ctr, Res Inst, Montreal, PQ, Canada
[7] Univ Toronto, Dept Pediat, Toronto, ON, Canada