1 School of Clinical Medicine, Qinghai University, Xining, Qinghai Province, 810000, China.
2 Department of Gynaecology and Obstetrics, Qinghai Red Cross Hospital, Xining, Qinghai Province, 810000, China; School of Clinical Medicine, Qinghai University, Xining, Qinghai Province, 810000, China. Electronic address: doctorwifi@126.com.
3 Department of Gynaecology and Obstetrics, Qinghai Red Cross Hospital, Xining, Qinghai Province, 810000, China. Electronic address: 2206774021@qq.com.
4 Department of Gynaecology and Obstetrics, Qinghai Red Cross Hospital, Xining, Qinghai Province, 810000, China. Electronic address: 349221622@qq.com.