NCLEX Question of the Day – Saturday, June 27, 2026

Today’s NCLEX question targets early recognition of magnesium toxicity in an obstetric patient. This matters because magnesium sulfate is commonly used to prevent seizures in preeclampsia, but it has a narrow safety range. A nurse who spots toxicity early can prevent respiratory failure, cardiac complications, and harm to both mother and baby.

Clinical Scenario

A 29-year-old client is admitted to the labor and delivery unit at 35 weeks of pregnancy with severe preeclampsia. Her blood pressure on admission was 168/108 mm Hg, and she reported a persistent frontal headache and blurred vision. The provider prescribed a magnesium sulfate infusion for seizure prevention. Four hours after the infusion started, the nurse reassesses the client.

The client is drowsy but answers questions appropriately. Her vital signs are: temperature 98.4 F, heart rate 68/min, respiratory rate 10/min, blood pressure 150/94 mm Hg, and oxygen saturation 95% on room air. Urine output for the last 2 hours is 40 mL total. Deep tendon reflexes are difficult to elicit at the patella bilaterally.

The Question

Which action should the nurse take first?

Answer Choices

1. A. Reposition the client to her left side and recheck blood pressure in 15 minutes
2. B. Stop the magnesium sulfate infusion and notify the provider
3. C. Increase the maintenance IV fluid rate to improve urine output
4. D. Encourage the client to take slow deep breaths and continue close observation

Correct Answer

B. Stop the magnesium sulfate infusion and notify the provider

Detailed Rationale

This client is showing several classic signs of magnesium toxicity: respiratory depression, low urine output, and diminished deep tendon reflexes. The first priority is to stop the source of the problem, which is the magnesium infusion.

Here is the step-by-step reasoning:

First, identify the danger signs. Magnesium sulfate depresses the central nervous system. As the magnesium level rises, reflexes decrease, respirations slow, and severe toxicity can progress to apnea or cardiac arrest. This client’s respiratory rate is 10/min, which is below the expected safe threshold. In many obstetric settings, a respiratory rate less than 12/min is a warning sign.

Second, connect urine output to magnesium buildup. Magnesium is excreted by the kidneys. This client’s urine output is 40 mL over 2 hours, which is only 20 mL/hour. That is low. When the kidneys do not clear magnesium well, the drug can accumulate quickly. This is why urine output is one of the most important ongoing assessments during a magnesium infusion.

Third, use reflexes as an early bedside clue. Deep tendon reflexes that are absent or difficult to elicit suggest rising magnesium levels. Reflex loss often appears before severe cardiac problems. In real nursing practice, this bedside finding matters because it gives the nurse an early warning before the client deteriorates further.

Fourth, act before calling. The question asks what the nurse should do first. NCLEX priority questions often test whether you know to stop a harmful medication immediately rather than wait for new orders. After stopping the infusion, the nurse should notify the provider, stay with the client, reassess respiratory status, and prepare to give calcium gluconate if prescribed. Calcium gluconate is the antidote because it helps reverse the effects of excess magnesium.

Fifth, monitor both maternal and fetal status. After stopping the infusion, the nurse should assess respiratory rate, oxygen saturation, lung sounds, level of consciousness, blood pressure, and fetal heart rate if the client is on continuous monitoring. The nurse should also review the most recent serum magnesium level if available, but treatment should not be delayed while waiting for lab results if toxicity is suspected from the assessment.

In short, this is a patient safety issue. The nurse must stop the magnesium infusion right away because the client already has signs that the medication is no longer safe at the current dose.

Why the Other Options Are Wrong

A. Reposition the client to her left side and recheck blood pressure in 15 minutes

Left-side positioning can support uteroplacental perfusion and may help in hypertensive pregnancy disorders, but it does not address the immediate problem. The client’s most urgent issue is possible magnesium toxicity, not just elevated blood pressure. Waiting 15 minutes would delay needed action.

C. Increase the maintenance IV fluid rate to improve urine output

This is unsafe without a provider’s order and clinical justification. Clients with preeclampsia are at risk for fluid overload and pulmonary edema. Low urine output in this setting is a warning sign, not a cue to give fluids automatically. The safer first step is to stop magnesium and report the findings.

D. Encourage the client to take slow deep breaths and continue close observation

This does not treat the cause. Coaching breathing may seem supportive, but a respiratory rate of 10/min in a client receiving magnesium sulfate is not something to observe casually. Continued infusion could worsen respiratory depression. The medication must be stopped.

Key Takeaways

• Magnesium sulfate is used to prevent seizures in preeclampsia, but it can become dangerous if it accumulates.
• Three major bedside warning signs are respiratory depression, decreased or absent deep tendon reflexes, and low urine output.
• If magnesium toxicity is suspected, stop the infusion first, then notify the provider.
• Calcium gluconate is the antidote typically used to reverse magnesium toxicity.
• Do not assume low urine output means the client just needs more IV fluids. In preeclampsia, extra fluid can make things worse.

• On-shift mini-checklist: Check respirations, reflexes, urine output, level of consciousness, and fetal status. Keep calcium gluconate available per unit protocol. Report changes early.

Quick Practice Extension

1. A postpartum client receiving magnesium sulfate has a respiratory rate of 14/min, urine output of 35 mL/hour, and 2+ reflexes. Which assessment finding should the nurse trend most closely over the next hour, and why?

2. A client with preeclampsia asks why the nurse keeps checking reflexes and urine output during the infusion. How would you explain this in simple patient-friendly language?

Category for today: OB

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