Background: Preeclampsia often affects young and nulliparous women, whereas older women are at great risk of chronic hypertension with superimposed preeclampsia. Magnesium sulphate is widely used in obstetrics, and is a drug of choice in two important complications of pregnancy, preeclampsia and preterm labor. Magnesium sulphate is used to prevent seizures in preeclampsia patients. Objective: To evaluate changes in Doppler velocimetry parameters of the umbilical artery together with continuous cardiotocography (CTG) parameters before and after magnesium sulphate administration in pregnant women with severe preeclampsia, and the possible effects of these changes on mode of delivery and neonatal outcome for fetal monitoring in these pregnant women. Patients and methods: A prospective observational cohort study was conducted at the Obstetrics and Gynecology Department, Al-Hussein and SayedGalalHospitals, Al-AzharUniversity. One hundred women with severe preeclampsia were included in the study. Cases were recruited from the emergency unit during the period from December 2020 to May 2020. Results: Patient's umbilical artery doppler showed a statistically significant decreased of RI and PI. Middle cerebral artery doppler showed a statistically significant decrease in RI and PI after 1 hours when it compared with baseline. Uterine artery doppler showed a statistically significant decrease of all uterine artery after 1 hours when it compared with baseline. All UA/MCA parameters decreased with no statistically significant differences. Conclusion: MgSO₄ proved to cause many hemodynamic changes as it has vasodilator effect on maternal and fetal blood vessels. Doppler indices in the umbilical (decrease in PI and RI) significantly changed after administration of MgSO₄ in pregnant women.