Which of the following is least likely to be a side effect of magnesium sulfate in preterm labor?

Magnesium sulfate is commonly used in the management of preterm labor due to its tocolytic properties. It's important to understand the side effects associated with this medication.

Hypertension is not typically associated with magnesium sulfate administration; in fact, magnesium sulfate may actually lead to hypotension (low blood pressure) instead. This is primarily due to its vasodilatory effects, which can lower blood pressure as it relaxes vascular smooth muscle. Therefore, the likelihood of experiencing hypertension as a side effect from magnesium sulfate is quite low compared to other adverse reactions.

Conversely, blurry vision, nausea, and flushing are more common side effects of magnesium sulfate treatment. Blurry vision can occur as a result of the central nervous system effects of magnesium, while nausea is a potential gastrointestinal side effect. Flushing is also frequently reported due to magnesium's effect on blood vessels, causing a feeling of warmth and redness of the skin. Thus, these characteristics make hypertension the least likely side effect of magnesium sulfate in the context of its use in preterm labor management.