1. Center for Reproductive Medicine, Department of Obstetrics and Gynecology Peking University Third Hospital Beijing China
2. National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital) Beijing China
3. Ministry of Education Key Laboratory of Assisted Reproduction (Peking University) Beijing China
4. Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproduction (Peking University Third Hospital) Beijing China