1. Department of Gynecology, Mindong Hospital Affiliated to Fujian Medical University, Fuan, Fujian 355000, P.R. China
2. Department of Gynecology, Xiamen Fifth Hospital, Xiamen, Fujian 361101, P.R. China
3. Department of Clinical Medicine, Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China