Maternal and newborn care
Preeclampsia and magnesium sulfate: what to watch
The signs that separate preeclampsia from severe features, how magnesium sulfate is given, and how to recognize and treat magnesium toxicity.
8 min read·core·
Reviewed by a licensed nurse · 2 November 2026
Gestational hypertension, preeclampsia, eclampsia
| Condition | Key features |
|---|---|
| Gestational hypertension | New hypertension after 20 weeks without proteinuria or organ involvement |
| Preeclampsia | New hypertension plus proteinuria or evidence of organ dysfunction |
| Preeclampsia with severe features | BP 160/110 or higher, neurologic signs, epigastric or right upper quadrant pain, abnormal labs, pulmonary edema |
| Eclampsia | Seizures in a client with preeclampsia |
| HELLP syndrome | Hemolysis, elevated liver enzymes, low platelets |
Nursing care during a magnesium infusion
- 01
Prepare
Seizure precautions, a quiet low-stimulation room, and calcium gluconate within reach. Use an infusion pump and follow the protocol for the loading dose.
- 02
Assess regularly
Deep tendon reflexes, respiratory rate, oxygen saturation, urine output, level of consciousness, blood pressure and fetal status at the protocol interval.
- 03
Recognize toxicity
Loss of deep tendon reflexes is an early sign. Then respiratory depression, a falling urine output, and cardiac changes.
- 04
Respond
Stop the infusion, call the provider, give oxygen, and give calcium gluconate as ordered.
Why urine output matters
- ·Magnesium is cleared by the kidneys, so low output raises the level.
- ·Output below 30 mL per hour, or about 100 mL over 4 hours, needs a report.
- ·Renal impairment increases the toxicity risk.
Other treatments
- ·Antihypertensives such as labetalol or hydralazine for severe-range pressures.
- ·Delivery is the definitive treatment, with timing based on gestational age and severity.
- ·Magnesium continues for about 24 hours after delivery in most protocols.
Check yourself
Did it stick?
1. A client receiving magnesium sulfate has absent patellar reflexes and a respiratory rate of 10. What should the nurse do first?
2. What is the primary purpose of magnesium sulfate in preeclampsia?
3. Which finding best indicates severe features of preeclampsia?
Sources
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Educational content for exam preparation. It is not clinical guidance and does not replace your facility's policies, current professional guidelines or the advice of a qualified clinician.