One of the common reasons for abnormal growth in the otherwise normal foetus is uteroplacental insufficiency and dysfunction. The aim of this paper assesses dexamethasone effects on fetal Umbilical and middle cerebral arteries as measured by Doppler ultrasonography after 24 hours following antenatal dexamethasone administration in cases of Placental insufficiency and impact of fetoplacental circulation variations on perinatal result. This study was a prospective cohort study that was conducted on 60 cases with singleton pregnancy were recruited from the 28th to the 36th weeks of gestation for administration of antenatal corticosteroids and were divided into two groups: Group A: 30 pregnant women complicated with placental insufficiency and Group B: 30 pregnant women with normal placental blood flow served as controls, at Al-Zahraa University Hospital of Al-Azhar University from November 2020 till November 2021. There is study showed that, following dexamethasone administration, group A showed a highly significant reduction in Umbilical artery RI, S/D ratio, middle cerebral artery-RI as compared with their baseline levels (P-value<0.001) and a significant difference in middle cerebral artery-RI and middle cerebral artery-PI (P-value = 0.002). Dexamethasone can improve blood flow in the foetal umbilical and middle cerebral arteries after only 24 hours of treatment in pregnant women with placental insufficiency, as measured by Doppler indices.