目的探讨米非司酮（ＲＵ４８６）在高危孕妇的促宫颈成熟和诱导宫缩中的作用。方法对６６例孕妇随机双盲对照观察，用药前及停药次日检查宫颈评分，试验组接受ＲＵ４８６２００ｍｇ１次／ｄ，共２ｄ，对照组给予相同剂量的安慰药；用药期间观察宫缩、胎心、宫颈评分，给予无应激试验胎心监护，常规检查血Ｅ３、ＨＰＬ及各种副反应。结果ＲＵ４８６具有良好的促宫颈成熟作用，其有效率达８７．８８％，明显高于对照组（２７．２８％）（Ｐ＜０．０１）；诱发宫缩和缩短产程方面明显优于对照组（Ｐ＜０．０１）；催产素用量小于对照组（Ｐ＜０．０５）；副反应主要为轻度恶心和呕吐。结论米非司酮对于高危孕妇具有促宫颈成熟和诱发宫缩、缩短产程的作用。 Objective To investigate the role of RU486 in promoting cervical ripening and inducing uterine contractions in high-risk pregnant women. Methods 66 cases of pregnant women were randomized double-blind control observation, before treatment and on the next day to check the cervical score, the test group received RU486200mg1 times / d, a total of 2d, the control group was given the same dose of placebo; medication observed contractions, fetal heart rate , Cervical score, given stress-free fetal heart rate monitoring, routine examination of blood E3, HPL and a variety of side effects. Results RU486 had a good cervical ripening effect, the effective rate was 87.88%, significantly higher than the control group (27.28%) (P <0.01); induced contractions and shorten the birth process was significantly better than the control group (P <0.01). The dosage of oxytocin was less than that of the control group (P <0.05). The side effects were mild nausea and vomiting. Conclusion Mifepristone can promote cervical ripening and induce uterine contractions and shorten the labor process in high-risk pregnant women.