Introduction
Introduction Hypertensive disorders are one of the most common medical problem encountered in pregnancy, affecting up to 15% of pregnancies and accounting for about 25% of antenatal admissions. Preeclampsia is part of a group of hypertensive disorders that complicate pregnancy. Hypocalcaemia, hypomagnesemia, hypokalemia and hypernatremia are associated with preeclampsia, and may have an important causative role in preeclampsia Post-partum magnesium sulfate is the gold standard in prevention of post-partum eclamptic fits which is given by different regimens for this purpose.

Aim of the work
The aim of this work was to study different regimens to evaluate the effective dose of magnesium sulfate in prevention of postpartum eclamptic fit, whether to give it over twenty-four hours, or forty-eight hours, or not given at all.

Patients
This prospective cohort study was conducted on 150 patients with severe preeclampsia diagnosed by clinical findings, laboratory investigations and ultrasonography admitted at Shatby university hospital in the period from July 2019 to March 2020.
They were classified into three groups: Group A (50 cases) not given postpartum magnesium sulfate, Group B (50 cases) given it over 24 hours and Group C (50 cases) given it over 48 hours.