Department of Obstetrics and Gynecology, Chongqing Qianjiang National Hospital, Chongqing, 409000;
Department of Obstetrics and Gynecology, Chongqing Qianjiang National Hospital, Chongqing, 409000;
Department of Obstetrics and Gynecology, Chongqing Jingxi Hospital, Chongqing, 409000;