1. Department of Obstetrics and Gynecology, Qilu Hospital of Shandong University, No. 107 Wenhuaxi Road, Jinan, Shandong 250012, China
2. Cryomedicine Lab, Qilu Hospital of Shandong University, No. 107 Wenhuaxi Road, Jinan, Shandong 250012, China
3. Department of Gynecology, The Central Hospital of Zibo, No. 54 Gongqingtuanxi Road, Zibo, Shandong 255036, China