A nurse is preparing a client for a Contraction Stress Test (CST).

Which method can be used to induce uterine contractions during the test?

An NST is a test that measures the fetal heart rate in response to fetal movement.

It is a non-invasive and simple way to assess fetal well-being.

An NST may be recommended to further evaluate fetal well-being if the CST result is equivocal, meaning that occasional but not persistent late decelerations are present.

Choice B. Amniocentesis is wrong because it is an invasive procedure that involves inserting a needle into the uterus to collect amniotic fluid for genetic testing or fetal lung maturity.

It is not used to evaluate fetal well-being in response to contractions.

Choice C. Magnetic resonance imaging (MRI) is wrong because it is an imaging technique that uses magnetic fields to create detailed pictures of the fetus and the placenta.

It is not used to evaluate fetal well-being in response to contractions.

Choice D. Chorionic villus sampling (CVS) is wrong because it is an invasive procedure that involves inserting a catheter or a needle into the placenta to collect chorionic villi for genetic testing.

It is not used to evaluate fetal well-being in response to contractions.

Normal ranges for CST are negative (normal) or positive (abnormal).

Equivocal and unsatisfactory are special categories of test outcomes that require further testing.

Normal ranges for NST are reactive (reassuring) ornon-reactive (non-reassuring).

To measure the fetal heart rate (FHR) in response to fetal movements.

This is because the FHR should increase by at least 15 beats per minute for at least 15 seconds when the fetus moves, which indicates a healthy and reactive fetus.

This is called an acceleration.

Choice B is wrong because the uterine contractions are not related to the fetal movements or the button pressing.

The uterine contractions are measured by a tocodynamometer or an intrauterine pressure catheter.

Choice C is wrong because the fetal oxygenation and neurological function are not directly measured by the button pressing.

The fetal oxygenation can be assessed by the FHR variability and decelerations, while the neurological function can be evaluated by other tests such as biophysical profile or fetal acoustic stimulation.

Choice D is wrong because the fetal well-being and hypoxia or distress are not indicated by the button pressing alone.

The fetal well-being and hypoxia or distress are determined by the FHR patterns, such as baseline, variability, accelerations and decelerations.