What test evaluates the fetal heart response to contractions?

The correct answer evaluates the fetal heart response specifically in relation to uterine contractions. The Contraction Stress Test (CST) is designed to assess how the fetal heart rate responds to contractions, which simulates the labor process. During this test, synchronized contractions (either spontaneous or induced) are monitored, and the fetal heart rate is analyzed for any signs of distress or changes.

In contrast, while the Non-Stress Test (NST) monitors fetal heart rate in a relaxed state without any contractions, it does not evaluate the response to contractions. The Biophysical Profile (BPP) combines several assessments including an NST, but again, does not specifically focus on fetal response to contractions alone. The Amniotic Fluid Index (AFI) measures the amount of amniotic fluid surrounding the fetus but does not provide information about fetal heart responses to contractions. Thus, the Contraction Stress Test is the only assessment directly focused on evaluating fetal heart responses in the context of uterine contractions.