Magnesium sulfate prophylaxis in preeclampsia: evidence from randomized trials.

Introduction In the United States, parenteral magnesium sulfate has been used for the prevention of recurrent seizures in patients with eclampsia for over 80 years. As a natural extension to its use for the treatment of eclamptic convulsions in the United States, magnesium sulfate was then adopted for seizure prophylaxis in women with varying degrees of hypertensive disorders of pregnancy. In 1990, I suggested that magnesium sulfate is the ‘‘ideal anticonvulsant in preeclampsia– eclampsia.’’ That recommendation was based on personal experience and the results of few observational studies available at that time. Until recently, this recommendation was criticized as being empiric and dogmatic because it had never been tested in large randomized trials. During recent years, several randomized trials were reported that compared the efficacy of magnesium sulfate with other anticonvulsants in eclamptic women. In these trials, magnesium sulfate was compared with diazepam, phenytoin, or a lytic cocktail. Only 1 of these trials was multicenter and had an adequate sample size. The results of these trials were summarized by Witlin and Sibai (Table 1). The overall results of these studies demonstrate that magnesium sulfate was associated with a significantly lower rate of recurrent seizures (relative risk [RR] = 0.41; 95% confidence interval [CI], 0.32–0.51) and lower rate of maternal death (RR = 0.62; 95% CI, 0.39–0.99) than that observed with other anticonvulsants (Table 2). Furthermore, there was a decreased rate of pneumonia, less need for mechanical ventilation, and fewer admissions to the intensive care unit in women receiving magnesium sulfate therapy. Therefore, there is level 1 Correspondence: Baha M. Sibai, MD, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267. E-mail: [email protected]