1. Department of Obstetrics and Gynecology, Jiading District Central Hospital Affiliated to Shanghai University of Medicine and Health Sciences, Shanghai 201800, P.R. China
2. Department of Pathology, Jiading District Central Hospital Affiliated to Shanghai University of Medicine and Health Sciences, Shanghai 201800, P.R. China
3. Department of Obstetrics and Gynecology, Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200127, P.R. China