1 Department of Obstetrics and Gynecology, The Reproductive Medical Center, West China Second University Hospital, Sichuan University, Chengdu 610041, China.
2 West China School of Medicine, Sichuan University, Chengdu 610041, China.
3 Key Laboratory of Birth Defects and Related of Women and Children of Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu 610041, China.