A multigravid client diagnosed with chronic hypertension is now in preterm labor at 34 weeks' gestation. The HCP has prescribed magnesium sulfate at 3 g/h. Which assessment finding indicates that the intended therapeutic effect has occurred?

A multigravid client diagnosed with chronic hypertension is now in preterm labor at 34 weeks' gestation. The HCP has prescribed magnesium sulfate at 3 g/h. Which assessment finding indicates that the intended therapeutic effect has occurred?

• A. Decrease in the frequency and number of contractions
• B. Increase in the fetal heart rate
• C. Worsening edema
• D. Decrease in maternal blood pressure

Answer: (B)

Magnesium sulfate used for tocolysis works by calming uterine smooth muscle, which reduces the frequency and strength of contractions. The best sign that the intended effect is occurring is a noticeable decrease in uterine activity—fewer contractions and less intensity—allowing more time for fetal lung maturity strategies like steroids to take effect. Fetal heart rate changes are not a reliable indicator of tocolysis success; an increased fetal heart rate would raise concern for distress rather than reflect that magnesium is working. Keep in mind other magnesium effects to watch for: maternal sedation, hypotension, or decreased reflexes as potential toxicity, and always monitor both maternal and fetal status closely.

Magnesium sulfate used for tocolysis works by calming uterine smooth muscle, which reduces the frequency and strength of contractions. The best sign that the intended effect is occurring is a noticeable decrease in uterine activity—fewer contractions and less intensity—allowing more time for fetal lung maturity strategies like steroids to take effect. Fetal heart rate changes are not a reliable indicator of tocolysis success; an increased fetal heart rate would raise concern for distress rather than reflect that magnesium is working. Keep in mind other magnesium effects to watch for: maternal sedation, hypotension, or decreased reflexes as potential toxicity, and always monitor both maternal and fetal status closely.