A 36-week gestation client with pregnancy-induced hypertension (PIH) is receiving an IV infusion of magnesium sulfate. Which assessment finding should the nurse report to the healthcare provider?

• A. Blood pressure of 100/60 mm Hg.
• B. Fetal heart rate of 120 to 125 beats/minute.
• C. Contractions occurring every 30 minutes.
• D. Respiratory rate of 11 breaths/minute.

Answer: (D)

Magnesium sulfate given for seizure prevention in PIH can depress the central nervous system and the respiratory drive. The most important signal to report is any sign of respiratory depression. A respiratory rate of 11 breaths per minute is below normal and suggests magnesium toxicity or overdose, so you should notify the provider promptly and be prepared to stop the infusion and administer calcium gluconate as ordered. Monitoring for other toxicity signs—such as decreasing deep tendon reflexes, oliguria, or changing mental status—helps catch problems early, but the respiratory rate is the immediate red flag in this scenario.

Other findings are less urgent on their own. A blood pressure of 100/60 mm Hg can be acceptable in the context of magnesium therapy, though you’d watch for hypotension. A fetal heart rate of 120–125 bpm falls within the normal range. Contractions every 30 minutes indicate minimal uterine activity and are not an acute concern in this setting.