1. Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China
2. National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China
3. Key Laboratory of Assisted Reproduction, Peking University, Ministry of Education, Beijing 100191, China
4. Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Beijing 100191, China