1. Department of Obstetrics and Gynecology Foshan Chancheng Central Hospital Foshan Guangdong China
2. Department of Epidemiology and Biostatistics School of Public Health Anhui Medical University Hefei Anhui China
3. Department of Library the First Affiliated Hospital College of Medicine Zhejiang University Hangzhou Zhejiang China
4. Foshan Institute of Fetal Medicine Affiliated Foshan Maternity & Child Healthcare HospitalSouthern Medical University Foshan Guangdong China
5. School of Integrated Traditional and Western Medicine Anhui University of Chinese Medicine Hefei Anhui China