A patient is admitted to labor and delivery for management of severe preeclampsia. An IV infusion of magnesium sulfate is ordered. What is the primary goal for magnesium sulfate therapy?

Choice A rationale Magnesium sulfate is a central nervous system depressant and a smooth muscle relaxant. While it can cause mild peripheral vasodilation which may result in a modest decrease in blood pressure, this is a secondary effect, not the primary therapeutic goal for severe preeclampsia management. Choice B rationale Proteinuria in preeclampsia results from generalized endothelial damage and increased glomerular capillary permeability in the kidneys. Magnesium sulfate does not directly target or reverse this underlying pathophysiological process; thus, decreasing proteinuria is not the primary therapeutic goal of this medication. Choice C rationale Magnesium sulfate acts as an anticonvulsant by decreasing neuromuscular excitability and reducing the amount of acetylcholine released at the neuromuscular junction. The reduction of deep tendon reflexes (DTRs) is an indicator of therapeutic drug level (normal is 1+ to 3+), not the primary goal itself. Choice D rationale Severe preeclampsia carries a high risk of eclamptic seizures, a life-threatening complication. Magnesium sulfate is the first-line drug therapy because its CNS depressant and vasodilatory effects elevate the seizure threshold, making seizure prevention the single most critical and primary goal of its administration.