A nurse is assessing a client for pre-term labor.

Which diagnostic test should the nurse anticipate being ordered for this client?

Tocolytics are a category of drugs used to delay the labor process.These may be used in situations when a pregnant person begins showing signs of preterm labor —which is any time before 37 weeks of completed pregnancy.Tocolytics may help delay labor by two to seven days.

Some possible explanations for the other choices are:

• Choice A. Administering intravenous fluids.

This is not a correct answer because intravenous fluids are not effective in suppressing uterine contractions.They may be used to correct dehydration or electrolyte imbalance, which can sometimes trigger preterm labor, but they are not a primary intervention for preterm labor.

• Choice C. Administering corticosteroids.

This is not a correct answer because corticosteroids are not tocolytics.They do not stop or slow down uterine contractions, but they help accelerate fetal lung maturity and reduce the risk of neonatal respiratory distress syndrome and other complications of prematurity.

Corticosteroids are often given along with tocolytics, but they have a different function and mechanism of action.

• Choice D. Administering antibiotics.

This is not a correct answer because antibiotics are not tocolytics.They may be used to treat infections that can cause or complicate preterm labor, such as chorioamnionitis or group B streptococcus, but they do not directly affect uterine contractions.

Antibiotics may be given along with tocolytics, but they have a different function.

The therapeutic effect of magnesium sulfate is to inhibit uterine contractions and prevent or delay preterm labor.

By assessing uterine activity, the nurse can evaluate if the medication is working or not.

Choice A is wrong because measuring urine output is not directly related to the therapeutic effect of magnesium sulfate, but rather to monitor for toxicity and renal function.

Choice B is wrong because checking deep tendon reflexes is also not directly related to the therapeutic effect of magnesium sulfate, but rather to monitor for neuromuscular effects and toxicity.

Choice D is wrong because monitoring blood pressure is not directly related to the therapeutic effect of magnesium sulfate, but rather to monitor for cardiovascular effects and toxicity.