Contraction Stress Test (CST)

Contraction Stress Test, commonly called CST, is an important antenatal test used to assess fetal well-being during pregnancy.

In this test, uterine contractions are produced deliberately to observe how the fetal heart rate responds under stress.

Why is CST also called Oxytocin Challenge Test?

CST is often referred to as the Oxytocin Challenge Test because oxytocin is commonly administered to initiate contractions.

These contractions act as a controlled stress, helping clinicians evaluate whether the fetus can tolerate reduced placental blood flow.

Why is it termed a Stress Test?

During uterine contractions, oxygen supply to the fetus slightly decreases. CST checks whether the fetal heart rate remains normal or shows late decelerations.

Because the fetus is exposed to physiological stress, CST is also known as a stress test.

✅ Key Point:
CST is known by both names — Oxytocin Challenge Test and Stress Test — which is why exam questions often test this concept.

📌 Disclaimer: This explanation is meant for nursing exam preparation and educational purposes only. Always follow standard obstetric textbooks and hospital protocols for clinical decisions.

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