1. Department of Gynecology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
2. Department of Obstetrics and Gynecology II, People’s Hospital of Gaotang County, Liaocheng, Shandong, China
3. Department of Reproductive Medicine, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
4. Department of Clinical Lab, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China