[1] Ottawa Hosp Res Inst, Clin Epidemiol Program, Ottawa, ON, Canada
[2] Univ Ottawa, Fac Med, Ottawa, ON, Canada
[3] Univ Ottawa, Hlth Sci Lib, Ottawa, ON, Canada
[4] Univ Ottawa, Heart Inst, Ottawa, ON, Canada
[5] Childrens Hosp Eastern Ontario Res Inst, 501 Smyth Rd,CPCR Bldg,Rm L1242, Ottawa, ON, Canada
[6] Univ Ottawa, Dept Obstet & Gynecol, Fac Med, Ottawa, ON, Canada