1. Center of Reproductive Medicine; Shanghai First Maternity and Infant Hospital; Tongji University School of Medicine; Shanghai China
2. Department of Gynaecology and Obstetrics; Ninth People's Hospital of Wuxi City; Wuxi Jiangsu Province China
3. Department of Obstetrics and Gynaecology; University of Hong Kong; Hong Kong China
4. Department of Gynaecology; Shanghai First Maternity and Infant Hospital; Tongji University School of Medicine; Shanghai China