1. Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu 610041, China
2. Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu 610041, China
3. Joint Laboratory of Reproductive Medicine, Sichuan University-The Chinese University of Hong Kong, Chengdu 610041, China