A nonstress test is used in pregnant women to evaluate the heart rate of an
developing baby (fetus). Normally, a developing baby's heart rate ranges from 100 to 160 beats per
minute, and it usually speeds up after the baby moves. If the heart rate is
faster or slower than this range or does not speed up after the baby moves, it
may mean that the baby is not doing well.
During the test:
- Elastic belts with two sensors are placed on the
woman's belly. The sensors are connected to an electronic monitoring machine.
- One sensor monitors the baby's heart
- The other sensor is a pressure gauge, which measures the
strength and length of tightening (contractions) of the woman's uterus if they
- The woman pushes a button on the machine every time
she feels the baby move.
- The baby's heart rate is compared during
movement and during contractions. Normally, the baby's heart rate increases
when the baby moves. But the heart rate may not increase during the
A nonstress test usually takes about 30 minutes. It can be done in a
hospital or the doctor's office.
Sarah Marshall, MD - Family Medicine
Alan C. Dalkin, MD - Endocrinology
November 3, 2011
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