1. Department of Obstetrics and Gynecology, First Affiliated Hospital, Heilongjiang University of Chinese Medicine, Harbin, China
2. Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Shatin, Hong Kong
3. Laboratory for Reproduction and Development, Li Ka Shing Institute of Health Sciences; School of Biomedical Sciences, Chinese University of Hong Kong-Suchuen University Joint Laboratory for Reproductive Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong