1. Department of Obstetrics and Gynecology, Nanjing Drum Tower Hospital Group Suqian Hospital and The Affiliated Suqian Hospital of Xuzhou Medical University, Suqian, Jiangsu 223800, P.R. China
2. Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210000, P.R. China
3. Department of Obstetrics and Gynecology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, P.R. China