1. Department of Reproductive Genetics, Hebei General Hospital, Shijiazhuang, Hebei 050051, P.R. China
2. Department of Reproductive Medicine, Tianjin Amcare Women and Children's Hospital, Tianjin 300381, P.R. China
3. Department of Reproductive Genetics, Bethune International Peace Hospital of The People's Liberation Army, Shijiazhuang, Hebei 050082, P.R. China
4. Department of Obstetrics and Gynecology Teaching and Research, Hebei Medical University, Shijiazhuang, Hebei 050017, P.R. China