1. Reproductive Medicine Center, Xi‘an People’s Hospital (Xi’an Fourth Hospital), Xi’an, Shaanxi Province, China
2. Department of Gynecology and Obstetrics, the First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi Province, China
3. Department of Obstetrics and Gynecology, Xi‘an Medical University, Xi’an, Shaanxi Province, China
4. Department of Obstetrics and Gynecology, Hainan Branch of PLA General Hospital, Sanya, China
5. Department of Obstetrics and Gynecology, Reproductive Medicine Center, Tangdu Hospital, Air Force Military Medical University, Xi’an, Shaanxi Province, China