METHOD:Pregnant rats on d3 of gestation were given ip cyclophosphamide(Cyc)10,20,40 mg/kg . On d4,the blastulation,the developmental phase of embryos and the frequency of degenerated blastocysts were evaluated.

• 方法：孕大鼠第3 天ip 环磷酰胺（Cyc 10 、20 、40mg/kg） ，孕第4 天评价胚胎的胚胎化作用，胚胎发育时相，及蜕变胚胎率；