Background& aim: Eclampsia is one of the major complications for patients with severe pre-eclampsia. Magnesium sulphate has been used as gold standard preventive treatment for a long time. Currently there is no consensus on the optimum duration of administration with maximum efficacy and less adverse events. In postpartum women with severe pre-eclampsia, the effectiveness of taking magnesium sulphate for 12 hours versus 24 hours was compared in this research. The objective was to maximize anticonvulsant action effectiveness while reducing magnesium sulphate adverse effect exposure.
Patients and Methods: A total of 280 women with severe preeclampsia were enrolled in the study. Those patients were randomly subdivided into group 1): received Mgso4 12- hour after delivery maintained at 1g per hour for 12 h and group 2): received Mgso4 24-hour after delivery maintained at 1g per hour for 24 h. All participants were subjected to thorough evaluation with recording demographic, obstetric and peripartum data.
Results: Both groups had insignificant differences as regard demographic, obstetric, clinical, laboratory, antepartum and intrapartum data. Administration of 12-hour magnesium sulfate as much as 24-hour magnesium sulfate was effective regard occurrence of eclampsia. Postpartum 12 hours group had significantly shorter duration of urinary catheter insertion (15.07 ± 11.01 vs. 28.11 ± 11.49 (h); p< 0.001) and length of hospital stay (2.52 ± 1.57 vs. 3.56 ± 1.69 (day); p< 0.001). Only one woman in 12 hours group had oliguria. There were three women in 12 hours group required prolongation of magnesium sulphate intake beyond the planned time.  
Conclusion: twelve hours postpartum magnesium sulphate intake could be beneficial in women with severe preeclampsia as regard prevention of eclampsia with fewer side effects.