1. Obstetrics and Gynecology Department, West China Second University Hospital Sichuan University Chengdu China
2. Obstetrics and Gynecology Department The Southwest Hospital of the Army Medical University Chongqing China
3. Obstetrics and Gynecology Department The First Affiliated Hospital of Chongqing Medical University Chongqing China
4. Obstetrics and Gynecology Department Sichuan Academy of Medical Sciences – Sichuan Provincial People's Hospital Chengdu China