1. Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
2. Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Nantong University and First People’s Hospital of Nantong City, Nantong, Jiangsu Province, China
3. State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu Province, China
4. Department of Obstetrics and Gynecology, Suqian People’s Hospital of Nanjing Drum-Tower Hospital Group, Suqian, Jiangsu Province, China
5. Key Laboratory of Pathogen Biology of Jiangsu Province, Department of Microbiology, Nanjing Medical University, Nanjing, China