[1] Cent South Univ, Xiangya Hosp, Dept Reprod Med, Changsha 410008, Peoples R China
[2] Huazhong Univ Sci & Technol, Union Hosp, Tongji Med Coll, Dept Obstet & Gynecol, Wuhan 430022, Peoples R China
[3] Huazhong Univ Sci & Technol, Union Hosp, Tongji Med Coll, Dept Pain Treatment, Wuhan 430022, Peoples R China