[1] St Michaels Hosp, Dept Obstet & Gynecol, Toronto, ON, Canada
[2] Univ Toronto, Sunnybrook Hlth Sci Ctr, Toronto, ON, Canada
[3] Univ Toronto, St Michaels Hosp, Dept Obstet & Gynecol, Div Maternal Fetal Med, Toronto, ON, Canada
[4] McMaster Univ, Dept Obstet & Gynecol, Div Maternal Fetal Med, Hamilton, ON, Canada
[5] McMaster Univ, Dept Radiol, Div Maternal Fetal Med, Hamilton, ON, Canada
[6] McMaster Univ, Dept Hlth Res Methods Evidence & Impact, Div Maternal Fetal Med, Hamilton, ON, Canada
[7] Univ Ottawa, Toronto, ON, Canada
[8] York Univ, Toronto, ON, Canada
[9] Univ Toronto, St Michaels Hosp, Dept Med, Toronto, ON, Canada
[10] Univ Toronto, St Michaels Hosp, Dept Obstet & Gynaecol, Toronto, ON, Canada
[11] Rotunda Hosp Dublin, Dept Obstet & Gynaecol, Dublin, Ireland
[12] McMaster Univ, Dept Obstet & Gynecol, Midwifery Educ Program, Toronto, ON, Canada