1. Department of Science and Education, Zigong Fourth People's Hospital, Zigong, Sichuan 643000, P.R. China
2. Department of Reproductive Medicine, Zigong Maternity and Child Healthcare Hospital, Zigong, Sichuan 643000, P.R. China
3. Department of Urology, Zigong Fourth People's Hospital, Zigong, Sichuan 643000, P.R. China