A newborn to a mother on magnesium sulfate therapy would be at risk for which finding related to the therapy?

A newborn to a mother on magnesium sulfate therapy would be at risk for which finding related to the therapy?

• A. Hypotension
• B. Hyperreflexia
• C. Hypoglycemia
• D. Seizures

Answer: (A)

Magnesium sulfate given to the mother crosses to the fetus and acts as a calcium channel blocker with CNS depressant effects. In the newborn, this exposure can relax smooth muscle and depress neuromuscular transmission, leading to signs such as hypotonia and possible respiratory depression. The vasodilating effect can contribute to lower blood pressure, so hypotension in the newborn is a plausible finding related to maternal magnesium therapy.

Hyperreflexia would not fit because magnesium reduces neuromuscular excitability, often causing decreased rather than increased reflexes. Hypoglycemia isn’t a known consequence of magnesium therapy, and seizures are something magnesium helps prevent, not increases the risk for.

If toxicity is suspected in the newborn, supportive care and calcium gluconate can be used as an antidote.