1. Department of Gynecology, Guizhou Provincial People’s Hospital, Guiyang, P.R. China
2. Department of Medical Record Statistics and Management, Guizhou Provincial People’s Hospital, Guiyang, P.R. China
3. Department of Gynecology, the Second Affiliated Hospital of Zunyi Medical University of Guizhou Province, Zunyi, P.R. China
4. Department of Gynecology, the Affiliated Hospital of Zunyi Medical University of Guizhou Province, Zunyi, P.R. China