Contraction Stress Test (CST) or Oxytocin Challenge test (OCT) is performed near the end of pregnancy to determine how well the fetus will cope with the contractions of childbirth. The aim is to induce contractions and monitor the fetus to check for heart rate abnormalities using a cardiotocograph.
Oxytocin challenge test — may be done during pregnancy to measure the baby’s heart rate during uterine contractions. Its purpose is to make sure the baby can get the oxygen he needs from the placenta during labor.
A negative CST is when there are 3 contractions / 10 minutes without fetal heart rate decelerations. A positive CST or OCT is defined as a test where more than 50% of contractions are associated with late decelerations.
