1. Medical School of Nantong University, Nantong 226000, China
2. Department of Obstetrics and Gynecology, Dongtai People’s Hospital, Yancheng 224000, China
3. Reproductive Medicine Center of Affiliated Hospital of Nantong University, Nantong 226000, China
4. Institute of Reproductive Medicine, Nantong University, Nantong 226000, China