1. Department of Gynecology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, P.R. China
2. Department of Gynecology and Οbstetrics, Changzhou Maternal and Child Health Care Hospital Affiliated to Nanjing Medical University, Changzhou, Jiangsu 213000, P.R. China
3. Department of Gynecology, Zhejiang Provincial People's Hospital, Hangzhou, Zhejiang 310014, P.R. China