1. Department of Obstetrics & Gynecology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, R.P. China
2. Department of Obstetrics & Gynecology, The People's Hospital of Yuhuan, Yuhuan, 317600, R.P. China
3. Department of Microbiology & Immunology, Wenzhou Medical University, Wenzhou, 325035, R.P. China