1. Department of Pathology, People's Hospital of Putuo District, Zhoushan, Zhejiang 316000, P.R. China
2. Department of Obstetrics and Gynaecology, Dinghai Central Hospital, Zhoushan, Zhejiang 316000, P.R. China
3. Department of Obstetrics and Gynaecology, People's Hospital of Putuo District, Zhoushan, Zhejiang 316000, P.R. China