1. Department of Reproductive Medicine, Longgang District Central Hospital of Shenzhen, Guangzhou University of Chinese Medicine, Shenzhen, P.R. China
2. Department of Obstetrics and Gynecology, The Second Xiangya Hospital of Central South University, Changsha, P.R. China
3. Department of Pathology, The Second Xiangya Hospital of Central South University, Changsha, P.R. China.