Reasons, Procedure and Preparation Required For a Contraction Stress Test

Submitted on March 27, 2012

Fetal Contraction Stress Test

A fetal contraction stress test is done to check if the unborn baby is going to remain healthy when the oxygen level is less during labor contractions. In this test, external fetal heart monitoring, which is a non-stress test is done when the would-be mother is 34 or more weeks pregnant.

When you have a uterine contraction, the oxygen and blood supply to the fetus dips low for a short period of time. While this doesn’t happen to all babies, the heart rate becomes slower for some. This change can be monitored through an external fetal monitoring device.

This contraction stress test is done by giving you the oxytocin hormone intravenously to cause labor contractions. You can also massage your nipples to signal your body to produce oxytocin. If the heart rate of the body slows down in a certain pattern after a contraction, then the baby might have problems during the actual labor.

This test is done generally for women who have an abnormal biophysical profile. Done with an ultrasound, a biophysical profile measures the physical characteristics of the baby. The level of amniotic fluid, fetal movements, fetal muscle tone, fetal breathing, uterine contractions are some of the things that are measured. This test is good for determining the health of the baby and is much better than the non-stress test. Also you may need to get more than one test done.

Reasons Why It is Conducted

This test check the following

  • If the baby is healthy when he or she is receiving less oxygen during labor contractions.
  • If the placenta is healthy enough to support the baby.
  • If the results of the biophysical profile or a non-stress test are not normal, then a contraction stress test might need to be done.


Like most medical tests, you will be asked not to drink or eat for four to eight hours before the test could begin. You will also need to empty your bladder before you have the test conducted. If you smoke, then it is advisable to keep away from smoking for about two hours prior to the test as smoking can lower the heart rate and activity of the baby.


This test is done by a doctor or an obstetrician or even by a trained nurse or laboratory technician. You will be asked to lie down on a bed with your back raised. You might be asked to tilt a bit to the left and two belts with sensors will be wrapped around your stomach. One of the sensors is for measuring uterine contractions, while the other one is for recording the heart rate of the baby. A low dose of oxytocin is injected until the woman has three contractions in ten minutes.