1. Obstetrics Department, Fuyang People’s Hospital, Fuyang, AnHui, China
2. Gynaecology and Obstetrics Department, People’s Hospital of Linquan County, Fuyang, Anhui, China
3. Gynecology Department, People’s Hospital of Jieshou City, Fuyang, Anhui, China
4. Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China