1. Department of Obstetrics and Gynecology, Jining No. 1 People’s Hospital, Jining, Shandong, China
2. Department of Obstetrics and Gynecology, Qilu Hospital of Shandong University, Jinan, Shandong, China
3. Department of Pathology, Jining No. 1 People’s Hospital, Jining, Shandong, China