目的　探讨米非司酮配伍米索前列醇终止早孕的最佳剂量方案 ,以预防流产后出血。方法　对 16 12例妊娠≤ 49天 ,要求药物终止妊娠的妇女 ,按 2∶1随机分为观察组、对照组。观察组1118例 ,米非司酮首次剂量 5 0mg ,继后每 12h 1次 ,每次 2 5mg(共 6d) ,总剂量 30 0mg ,于用药第 3天晨加用米索前列醇 6 0 0 μg,第 4～ 6天晨各加服 2 0 0 μg,总量 12 0 0 μg。对照组 494例 ,米非司酮首次剂量 5 0mg ,继后每 12h 1次 ,每次 2 5mg ,总剂量 15 0mg ,于用药第 3天晨加服米索前列醇 6 0 0 μg。 结果　观察组与对照组完全流产率分别为 98 39%和 88 0 6 % ;不全流产率 1 43 %和 10 73 % ,流产失败率为 0 18%和 1 2 1% (P <0 0 0 0 1)。两组出血时间分别为 (8 2± 2 8)d和 (12 3± 3 9)d(P <0 0 0 1) ,10d内止血率为 87 45 %和 5 7 47% (P <0 0 0 0 1) ,两组副反应比较 ,差异无显著性 (P >0 0 5 )。结论　低剂量分次服用并延长米非司酮并米索前列醇用药时间可提高完全流产率 ,缩短药物流产后出血时间 ,且不增加副反应 Objective To explore the optimal dose of mifepristone with misoprostol for termination of early pregnancy to prevent bleeding after abortion. Methods A total of 16 12 pregnant women ≤ 49 days of pregnancy requiring termination of pregnancy were randomly divided into observation group and control group according to 2: 1. The observation group of 1118 cases, the first dose of mifepristone 50mg, followed by every 12h 1, each 25mg (total 6d), a total dose of 300mg, on the 3rd day of treatment with misoprostol 600 μg, on the 4th to 6th morning each add 200 μg, the total amount of 1200 μg. Control group, 494 cases, the first dose of mifepristone 50mg, followed by every 12h 1, each 25mg, a total dose of 15 0mg, in the morning of the third day of administration add misoprostol 600o. Results The rate of complete abortion in observation group and control group was 98 39% and 88 6% respectively. The rate of incomplete abortion was 143% and 10 73% respectively, and the abortion rate was 0 18% and 121% (P <0 0 0 0) 1). The bleeding time was (82 ± 2 8) d and (123 ± 39) days respectively in two groups (P <0 0 01), the rate of hemostasis was 87 45% and 57 47% within 10 days There was no significant difference in the side effects between the two groups (P> 0.05). Conclusions Low dose and prolonged administration of mifepristone and misoprostol can increase the rate of complete abortion, shorten the bleeding time after medical abortion, without increasing side effects