28周脐血流阻力指数增高

健康咨询描述：孕期26周脐动脉:MAX56VM/S，MIN:12CM/S，RI:0.78，S/D:4.4528周脐动脉:MAX58VM/S，MIN:10CM/S，RI:0.81，S/D:5.33；大脑中动脉:MAX65VM/S，MIN:10CM/S，RI:0.96，S/D:6.5。想得到的帮助：该如何是好