1. Reproductive Medical Center, 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 of Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu 610041, China
3. Department of Ultrasonography, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
4. Reproductive Endocrinology and Regulation Laboratory, West China Second University Hospital, Sichuan University, Chengdu 610041, China
5. Sichuan University-The Chinese University of Hong Kong Joint Laboratory for Reproductive Medicine, Sichuan University, Chengdu 610041, China
6. West China School of Medicine, Sichuan University, Chengdu, Sichuan 610041, China
7. Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu 610041, China