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. Key Laboratory of Assisted Reproduction, Peking University, Ministry of Education, Beijing, China
4. Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Peking University Third Hospital, Beijing, China