Affiliation: | 1. Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical SciencesBeijingChina;2. Department of Gynecology, The First Affiliated Hospital of Guangzhou Medical UniversityGuangzhou, GuangdongChina;3. Department of Obstetrics and Gynecology, Beijing HospitalBeijingChina;4. Department of Gynecology, The Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhou, GuangdongChina |