1. Department of Gynecologic Oncology, Qingdao Central Hospital, Qingdao, China.
2. Department of Reproductive Center, Qingdao Hospital for Women and Children, Qingdao, China.
3. Department of Obstetrics, Rizhao People's Hospital, Rizhao, China.
4. Department of Emergency, Qingdao Central Hospital, Qingdao, China.