1. Department of Eugenic Genetics, Guiyang Maternal and Child Health Care Hospital, Guiyang, Guizhou 550003, P.R. China
2. Department of Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, Guiyang, Guizhou 550004, P.R. China
3. Department of Assisted Reproduction, Guiyang Maternal and Child Health Care Hospital, Guiyang, Guizhou 550003, P.R. China