1. Department of Gynaecology and Obstetrics, The First Hospital of Jilin University, Changchun, China
2. Department of Anesthesiology, The First Hospital of Jilin University, Changchun, China
3. Department of Gynaecology and Obstetrics, Qingyuan People’s Hospital, Qingyuan, China
4. Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, China