Magnesium sulfate is used in preeclampsia for what purpose?

• A. Lower blood pressure
• B. Promote labor
• C. Prevent seizures
• D. Improve fetal respiration

Answer: (C)

In preeclampsia, the main danger to the mother is progression to seizures; magnesium sulfate is given to prevent those seizures. It works as a central nervous system depressant and anticonvulsant, lowering neuronal excitability and stabilizing nerve transmission. This seizure prophylaxis is the primary purpose, not lowering blood pressure, initiating labor, or improving fetal respiration.

Lowering blood pressure is managed with antihypertensive medications, while labor is not promoted by magnesium sulfate. Fetal respiration isn’t the target here—the aim is maternal stabilization to reduce seizure risk, which in turn supports the fetus by maintaining a safer intrauterine environment.

Clinicians monitor for signs of toxicity during therapy, such as diminished reflexes, slowed respiration, and reduced urine output, and adjust treatment accordingly.