What Is The Non-Stress Test?

Many women undergo tests during pregnancy to check for birth defects, genetic disorders, and other problems. Find out more here about the non-stress test (or NST), used in the third trimester to check how the baby is reacting to life in the womb.
What it is
A nonstress test (NST) (measures the response of the baby's heart rate to each movement the baby makes as reported by mother or seen by a doctor on an ultrasound screen). The "non-stress" part of this test's name refers to the fact that no medication is given to the mother to cause movement of the fetus or contraction of the uterus.

It is often used to confirm the well-being of the baby, based on the principle that a healthy fetus will demonstrate an acceleration in its heart rate following movement, such as rubbing the mother's abdomen or making a loud noise above the abdomen with a special device (a buzzer of sorts).

When movement of the fetus is noted, a recording of the fetal heart rate is made. If the heart rate goes up, the test is normal. if the heart rate does not accelerate, the fetus may be merely be "sleeping"; if, after stimulation, the fetus still does not react, it may be necessary to perform a "contraction stress test" (aka the "oxytocin challenge test" or simply "stress test").

What's it like for the mom? Here's what one Pregnancy & Baby reader had to say. "I went to the OB this morning, and they hooked me to a fetal monitor to perform a non-stress test to check the movements and reaction of the baby and placenta. The baby moved around a lot. I had a clicker to hold, and everytime I felt a movement, I pressed down on the blue button -- and I pressed it a lot. The doctor came in, read the tape coming out of the monitor, smiled, and said everything looked good. He said I even had one contraction."PregnancyAndBaby.com

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