1. Department of Obstetrics and Gynecology, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China;
2. China-Canada-New Zealand Joint Laboratory of Maternal and Fetal Medicine, Chongqing Medical University, Yuzhong District, China;
3. Department of Orthopedics, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China