1. The Department of Infectious Disease, First Affiliated Hospital of Medicine College, Xi’an Jiaotong University, Xi’an, Shaanxi, China;
2. The Department of Rheumatism, First Affiliated Hospital of Medicine College, Xi’an Jiaotong University, Xi’an, Shaanxi, China;
3. The department of obstetrics, Shaanxi Kangfu Hospital, Xi’an, Shaanxi, China;
4. The department of obstetrics, The Second Affiliated Hospital of Shaanxi Traditional Chinese Medical College, Xianyang, Shaanxi, China;
5. The department of obstetrics, Shangluo Central Hospital, Shangluo, Shaanxi, China;
6. Institute of Neurobiology, Department of Human Anatomy and Histoembryology, Medicine College, Xi’an Jiaotong University, Xi’an, Shaanxi, China