目的 :了解小剂量米非司酮 (10 0 mg)用于足月妊娠引产时胎盘超微结构的变化。方法 :对 2 0例米非司酮配伍米索前列醇引产 ,2 0例单用米索前列醇引产 ,2 0例自然临产 ,无明显并发症及合并症 ,经阴道分娩的足月初产妇胎盘进行透射电镜观察并通过图像分析仪对胎盘超微结构进行体视学分析。结果 :米非司酮组需用米索前列醇的次数较单用米索前列醇组明显减少。合体滋养细胞、细胞滋养细胞、蜕膜细胞、绒毛中毛细血管内皮细胞的超微结构在三组间未发现明显不同。结论 :足月孕妇口服米非司酮 10 0 mg配伍米索前列醇引产对胎盘无明显影响 ,并未造成胎儿、胎盘缺血缺氧性损害。 Objective: To investigate the effect of low dose mifepristone (100 mg) on ​​the changes of placental ultrastructure in term labor induction of labor. Methods: 20 cases of mifepristone with misoprostol induction of labor, 20 cases of misoprostol alone induced labor, 20 cases of natural labor, no significant complications and complications, vaginal delivery of full-term maternal placenta Transmission electron microscopy and image analysis of the placenta ultrastructure Stereological analysis. Results: The number of misoprostol used in the mifepristone group was significantly lower than that of the misoprostol alone group. The ultrastructure of capillaries endothelial cells in syncytiotrophoblasts, cytotrophoblasts, decidual cells and villi were not significantly different among the three groups. Conclusion: The full-term pregnant women oral mifepristone 10 mg with misoprostol induction of labor has no significant effect on the placenta, did not cause fetal, placental ischemia and hypoxia damage.