1. Department of Obstetrics and Gynecology, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Province 533000, China
2. Department of Obstetrics and Gynecology, People’s Hospital of Baise, Baise, Guangxi Province 533000, China
3. Department of Pathology, The Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Province 533000, China
4. Department of Human Anatomy, Guangxi Medical University, Nanning, Guangxi Province 530021, China