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Prenatal Test: Contraction Stress Test

What Is a Contraction Stress Test?

A contraction stress test measures the fetal heart rate after the uterus is stimulated to contract. This is done to make sure that during labor the fetus can handle contractions and get the oxygen needed from the placenta.

Why Are Contraction Stress Tests Done?

This test may be recommended when a nonstress test or biophysical profile (BPP, an ultrasound done with a nonstress test) indicates a problem. It can determine whether the baby's heart rate remains stable during contractions.

Should I Have a Contraction Stress Test?

Your doctor may schedule a contraction stress test if concerned about how your baby will respond to contractions or to determine the fetal heart rate response to stimulation. However, the test can induce labor.

What Happens During a Contraction Stress Test?

In this test, the uterus is stimulated with pitocin, a synthetic form of oxytocin (a hormone secreted during childbirth). This is done with injections of pitocin or by squeezing the mother's nipples (causing oxytocin to be secreted). The pitocin brings on mild contractions, letting doctors see the effect of contractions while monitoring the baby's heart rate.

When Are Contraction Stress Tests Done?

A contraction stress test can be done at 34 weeks or later.

When Are the Results Available?

Results of a contraction stress test are ready immediately.

Date reviewed: May 2018