[1] Qingdao Women & Childrens Hosp, Obstet Dept, Qingdao, Peoples R China
[2] Qingdao Blood Ctr, Inst Transfus Med, Qingdao, Peoples R China
[3] Qingdao Women & Childrens Hosp, Urol Dept, Qingdao, Peoples R China
[4] Qingdao Women & Childrens Hosp, Urol Dept, 6 Tongfu Rd, Qingdao 266071, Shandong, Peoples R China