1. Department of Obstetrics and Gynecology, Chongqing Xinqiao Hospital, Second Affiliated Hospital of Army Medical University, Chongqing, China
2. Dapartment of Gynecology, Xianning Central Hospital (The first Affiliated Hospital of Hubei University of Science and Technology), Xianning, Hubei, China
3. Department of Obstetrics and Gynecology, Wuhan Hanyang hospital, Wuhan, China