1. Reproductive Medical Center, Renmin Hospital of Wuhan University and Hubei Clinic Research Center for Assisted Reproductive Technology and Embryonic Development, Wuhan, Hubei 430060, P.R. China
2. Yichang Central People's Hospital, Yichang, Hubei 443000, P.R. China
3. Department of Gynecology and Obstetrics, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China