Abstract： Aim To investigate the value of middle cerebral artery(MCA)and maternal uterine artery(UtA)blood flow combined with serum miR-424 in the prognosis of fetal growth restricted(FGR)fetuses in the second trimester.Methods A total of 87 FGR pregnant women were selected as the observation group and 124 healthy pregnant women were selected as the control group.FGR pregnant women were divided into poor prognosis group and good prognosis group according to the prognosis.Fetal MCA,mater-nal UtA blood flow and serum miR-424 were compared among all groups.ROC was used to evaluate the prognostic value of fetal MCA,UtA blood flow and serum miR-424 in FGR.Results Serum miR-424 in the observation group was higher than that in the control group,and the poor prognosis group was higher than that in the good prognosis group(P＜0.05).Fetal MCA pulse index(PI)and blood flow resistance index(RI)in observation group were lower than those in control group,and those in poor prognosis group were lower than those in good prognosis group(P＜0.05).The UtA PI and RI in the observation group were higher than those in the control group,and the poor prognosis group was higher than that in the good prognosis group(P＜0.05).The combined detec-tion of fetal MCA,maternal UtA blood flow and serum miR-424 had a good predictive value for prognosis of fetal FGR(P＜0.05).Conclusion The combined detection of fetal MCA,maternal UtA blood flow and serum miR-424 has better predictive effect on prog-nosis of fetal FGR,and has higher clinical application value compared with single detection.