1 Department of Obstetrics and Gynecology, Peking University First Hospital, Beijing 100034, China.
2 Beijing Key Laboratory of Maternal Fetal Medicine of Gestational Diabetes Mellitus, Beijing 100034, China.
3 Key Laboratory for Major Obstetric Diseases of Guangdong Province, Department of Gynaecology and Obstetrics, Third Affiliated Hospital of Guangzhou Medical University, Guangdong 510150, China.