1. Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College Huazhong University of Science and Technology Wuhan China
2. Department of Obstetrics Renmin Hospital of Wuhan University Wuhan China
3. School of Public Health, Tongji Medical College Huazhong University of Science and Technology Wuhan China
4. Department of Obstetrics, Xianning Central Hospital The First Affiliated Hospital of Hubei University of Science And Technology Xianning China
5. Department of Obstetrics, Maternal and Child Health Hospital of Hubei Province, Tongji Medical College Huazhong University of Science and Technology Wuhan China