[1] China Med Univ, Shengjing Hosp, Dept Obstet & Gynecol, Ctr Reprod Med, Shenyang 110004, Liaoning, Peoples R China
[2] China Med Univ, Dept Clin Epidemiol, Shengjing Hosp, Shenyang 110004, Liaoning, Peoples R China
[3] China Med Univ, Dept Pediat, Shengjing Hosp, Shenyang 110004, Liaoning, Peoples R China
[4] Yale Sch Med, Dept Obstet Gynecol & Reprod Sci, New Haven, CT 06520 USA
[5] Dalian Municipal Womens & Childrens Med Ctr, Reprod & Genet Med Ctr, Dalian 116031, Peoples R China
[6] Jinghua Hosp, Ctr Human Reprod & Genet, Shenyang 110000, Liaoning, Peoples R China
[7] Shenyang Womens & Childrens Hosp, Ctr Reprod Med, Shenyang 110011, Liaoning, Peoples R China
[8] Harvard Med Sch, Harvard Inst Med, Brigham & Womens Hosp, Dept Med, Boston, MA 02115 USA