1. Department of Obstetric and Gynecology, Renmin Hospital of Wuhan University, Wuhan 430000, China
2. Department of Gynecology, The First Affiliated Hospital of Xinjiang Medical University, Urumchi 830001, China
3. Department of Human Anatomy and Embryology, Chengdu Medical College, Chengdu 610000, China
4. Department of Gynecology and Obstetrics, Xinjiang Production and Construction Corps 13 Division Red Star Hospital, Hami City 839000, China