Objective To study placental microcirculation and microstructure of pregnant women with pregnancy-induced hyper-tension by using MRI intravoxel incoherent motion(IVIM)at plateau area.Methods A retrospective analysis was performed on 22 healthy pregnant women at third trimester with single birth and 20 pregnant women with pregnancy-induced hypertension.All subjects underwent ultrasound,routine MRI and IVIM examination.The D,D*,f values of the whole placental and various parts of the placental,estimated fetal weight(EFW)and postnatal weight were measured and recorded.The differences of two groups data were analyzed by independent sample t test or one-way analysis of variance,and then multiple comparisons of placental quantitative parameters between the two groups were analyzed by Bonferroni method.Results The fetal side and whole placental f values in healthy pregnant women at third trimester were higher than pregnancy-induced hypertension(P＜0.05),the maternal side and whole placental D values in healthy pregnant women at third trimester were higher than pregnancy-induced hypertension(P＜0.05),the EFW and fetal birth weight in healthy pregnant women at third trimester were higher than pregnancy-induced hypertension(P＜0.05).Conclusion IVIM can effectively evaluate placental blood flow microcirculation and microstructure with pregnancy-induced hypertension at plateau area,and provide a new proof for clinical evaluation of placental structure and function changes.