1. Department of Social Work and Social Administration, University of Hong Kong, Hong Kong
2. Department of Obstetrics & Gynaecology, University of Hong Kong-Shenzhen Hospital, Futian, Shenzhen, China
3. Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
4. Department of Obstetrics and Gynecology, Military General Hospital of Beijing PLA, Beijing, China
5. Department of Gynecology and Obstetrics, Inner Mongolia Medical University Affiliated Hospital, Inner Mongolia, China
6. Department of Obstetrics & Gynaecology, University of Hong Kong, Hong Kong