 Women agreeing to participate in the study will receive a loading dose and maintenance therapy using an IV infusion administered by the Springfusor pump. Women will receive a 8 mL loading dose containing 4g magnesium sulfate heptahydrate MgSO47H2O 50 solution, which is approximately 2 mmoL magnesiummL. The loading dose of 8mL with 4 g MgSO4 will be administered using the Springfusor pump. The administration of the loading dose will be immediately followed by a maintenance infusion. The maintenance dose of 4 g 8 cc, 50 MgSO4 will be administered with the Springfusor pump continuously over four hours. Clinical monitoring will occur once every hour during the treatment period. Clinical monitoring will occur throughout the treatment, with reflexes, urine output and respiration to be checked at least every hour or, if more frequent, as per standard practice at the study site. The pump will be checked at each monitoring visit. Prior to discharge from the study, patients will be asked to assess their opinions about the acceptability and ease of use of the mode of administration. All requests or inquiries about termination of treatment will be recorded. 