Chinese Academy of Medical Sciences - Department of Obstetrics and Gynecology, Chinese Academy of Medical Sciences - Department of Obstetrics and Gynecology, Chinese Academy of Medical Sciences - Department of Obstetrics and Gynecology, Chinese Academy of Medical Sciences - Department of Obstetrics and Gynecology, Chinese Academy of Medical Sciences - Department of Obstetrics and Gynecology, Chinese Academy of Medical Sciences - Department of Obstetrics and Gynecology, Chinese Academy of Medical Sciences - Department of Obstetrics and Gynecology and Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC) - Department of Obstetrics and Gynecology

Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC) - Department of Obstetrics and Gynecology, Sichuan University - Chinese Evidence-Based Medicine Centre, Tufts University - Deparment of OBGYN, Central South University - Department of Obstetrics and Gynecology, Wuxi Maternal and Child Health Care Hospital - Department of Obstetrics and Gynecology, Maternal and Child Health Care Hospital Changsha - Department of Obstetrics and Gynecology, Southern Medical University - Department of Gynecology, Xinjiang Medical UniversityXinjiang Medical University - Department of Obstetrics and Gynecology, Government of the People's Republic of China - Department of Obstetrics and Gynecology, Shandong University - Department of Obstetrics and Gynecology, Guangzhou Medical University - Department of Obstetrics and Gynecology, People's Hospital of Xinjiang Autonomous Region - Department of Gynecology, Sichuan University - Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education, Klinik Tettnang - Department of Obstetrics and Gynecology, Kaohsiung Chang Gung Memorial Hospital, Yale University - Department of Biostatistics, Sichuan University - Chinese Evidence-Based Medicine Centre and Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC) - Department of Obstetrics and Gynecology

Chinese Academy of Medical Sciences - Department of Obstetrics and Gynecology, Chinese Academy of Medical Sciences - Department of Obstetrics and Gynecology, Southern Medical University - Department of Gynaecology and Obstetrics, Chinese Academy of Medical Sciences - Department of Obstetrics and Gynecology, Chinese Academy of Medical Sciences - Department of Obstetrics and Gynecology, Chinese Academy of Medical Sciences - Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences - Department of Epidemiology and Statistics, Children’s Hospital of Shanxi Province, Maternal and Child Health Hospital of Wuxi, Maternal and Child Health Hospital of Gansu Province, Maternal and Child Health Hospital of Foshan, Guiyang Maternal and Child Health Care Hospital, China Medical University - Department of Obstetrics and Gynecology and Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC) - Department of Obstetrics and Gynecology

Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC) - Department of Obstetrics and Gynecology and Please see PDF for full list of authors & affiliations

Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC) - Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC) - Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC) - Department of Obstetrics and Gynecology and Please see PDF for full list of authors & affiliations