[1] Shanghai Jiao Tong Univ, Sch Med, Xinhua Hosp, Dept Obstet & Gynecol, 1665 Kongjiang Rd, Shanghai 200092, Peoples R China
[2] Ottawa Hosp Res Inst, Clin Epidemiol Program, OMNI Res Grp, Ottawa, ON, Canada
[3] Cent S Univ, Xiangya Hosp, Dept Dermatol, Changsha, Hunan, Peoples R China
[4] Better Outcomes Registry & Network Ontario, Ottawa, ON, Canada
[5] Childrens Hosp Eastern Ontario, Res Inst, Ottawa, ON, Canada
[6] Univ Ottawa, Sch Epidemiol & Publ Hlth, Ottawa, ON, Canada
[7] Univ Saskatchewan, Regina Gen Hosp, Maternal Fetal Med, Reginal, SK, Canada
[8] Univ Ottawa, OMNI Res Grp, Fac Med, Dept Obstet & Gynecol, 501 Smyth Rd, Ottawa, ON K1H 8L6, Canada