1. Department of Obstetrics and Gynecology; China Meitan General Hospital; Beijing China
2. Department of Radiation Oncology; Peking University School of Oncology, Peking University Cancer Hospital; Beijing China
3. Department of Obstetrics and Gynecology; Beijing Fengtai Hospital, Affiliated Capital Medical University; Beijing China
4. China Academy of Chinese Medical Sciences; Wangjing Hospital; Beijing China