1. Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Soochow University, No. 1055, Sanxiang Road, Suzhou, Jiangsu 215000, China
2. Center for Reproductive Medicine, XuZhou Central Hospital, No. 199, Jiefang Road, Xuzhou, Jiangsu 221009, China
3. Department of Obstetrics and Gynecology, XuZhou Central Hospital, No. 199, Jiefang Road, Xuzhou, Jiangsu 221009, China