[1] Shanghai Jiao Tong Univ, Xinhua Hosp, Early Life Hlth Inst, Minist Educ,Shanghai Key Lab Childrens Environm Hl, KongJiang Rd, Shanghai 200092, Peoples R China
[2] Univ Toronto, Lunenfeld Tanenbaum Res Inst, Fac Med, Prosserman Ctr Populat Hlth Res,Dept Obstet & Gyne, L5-240,Murray St 60, Toronto, ON M5T 3H7, Canada
[3] Shanghai Jiao Tong Univ, Int Peace Matern & Child Hlth Hosp, Obstet & Gynecol, Sch Med, Shanghai 200030, Peoples R China
[4] Shandong First Med Univ, Shandong Acad Med Sci, Clin Skills Ctr, Sch Clin Med, Jinan, Peoples R China
[5] Shanghai Jiao Tong Univ, Xinhua Hosp, Obstet & Gynecol, Sch Med, Shanghai 200092, Peoples R China
[6] Shanghai Jiao Tong Univ, Xinhua Hosp, Dept Clin Assay Lab, Sch Med, Shanghai 200092, Peoples R China
[7] Nanjing Med Univ, Sch Publ Hlth, Dept Epidemiol, State Key Lab Reprod Med, Nanjing, Peoples R China