1. Department of Urology, North China University of Science and Technology Affiliated Hospital, Tangshan, Hebei 063000, P.R. China
2. Department of Obstetrics and Gynecology, Tangshan Hongci Hospital, Tangshan, Hebei 063000, P.R. China
3. Department of Intensive Care Units, Tangshan People's Hospital, Tangshan, Hebei 063000, P.R. China