Contraction Stress Test
Oxytocin Challenge Test
Test Overview
A contraction stress test checks to see if your unborn baby (fetus) will stay healthy during the reduced oxygen levels that normally occur during contractions when you are in labor. This test includes external fetal heart monitoring
. The test is done when you are 34 or more weeks pregnant.
During a uterine contraction, the blood and oxygen supply to your baby drops for a short time. This is not a problem for most babies. But the heart rate of some babies gets slower. This change in heart rate can be seen on the external fetal monitoring device.
For a contraction stress test, the hormone oxytocin is given to you in a vein (intravenously, or IV) to cause labor contractions. You may also massage your nipples. This tells your body to release oxytocin. If your baby's heart rate slows down (decelerates) in a certain pattern after a contraction instead of speeding up (accelerating), your baby may have problems with the stress of normal labor.
A contraction stress test is usually done if you have an abnormal nonstress test or biophysical profile. A biophysical profile uses ultrasound during a nonstress test to measure a series of physical characteristics of your baby. You may have more than one contraction stress test during your pregnancy.
Some doctors may do a biophysical profile or a Doppler ultrasound test instead of a contraction stress test.
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| Author: | Maria Essig | Last Updated: February 10, 2010 |
| Medical Review: | Sarah Marshall, MD - Family Medicine Femi Olatunbosun, MB, FRCSC - Obstetrics, Gynecology and Reproductive Medicine | |
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| Topic Contents | |
 | Test Overview |
| Why It Is Done | |
| How To Prepare | |
| How It Is Done | |
| How It Feels | |
| Risks | |
| Results | |
| What Affects the Test | |
| What To Think About | |
| References | |
| Credits | |