[1] Tongji Univ, Shanghai Peoples Hosp 4, Sch Med, Dept Obstet & Gynecol, Shanghai, Peoples R China
[2] Tongji Univ, Shanghai Matern & Infant Hosp 1, Sch Med, Dept Gynecol, Shanghai, Peoples R China
[3] Tongji Univ, Shanghai Peoples Hosp 10, Sch Med, Dept Obstet & Gynecol, Shanghai, Peoples R China