1. Department of Obstetrics and Gynecology, Second Hospital of Shaanxi, Xi’an, China;
2. First Affiliated Hospital, Xi’an Jiaotong University Health Sciences Center, Xi’an Jiaotong University, Xi’an, China;
3. Department of Biomedical Engineering, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, China;
4. Department of Epidemiology & Biostatistics, School of Public Health, Xi’an Jiaotong University Health Sciences Center, Xi’an Jiaotong University, Xi’an, China