1. Department of Obstetrics and Gynecology, Shanghai First People's Hospital Affiliated to Nanjing Medical University, Nanjing, China
2. Center for Reproductive Medicine, Affiliated Hospital of Weifang Medical University, Weifang, China
3. Department of Gynecology and Obstetrics, Nanjing Maternal and Children Care Hospital Affiliated to Nanjing Medical University, Nanjing, China
4. Department of Obstetrics and Gynecology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China