A test to check on how the baby is doing while inside the uterus. A CST tests how the baby responds to the stress of uterine  contractions. The mother is hooked up to a fetal monitor and is given oxytocin via an IV, while the baby is monitored to see how it responds to contractions.

A contraction stress test (CST) 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 the contractions and monitor the baby to check for heart rate abnormalities. It involves the release of oxytocin into the blood stream of the pregnant woman by the stimulation of the nipples.