Due to special situations, your provider may decide to order a non-stress test (NST). An NST monitors a baby's health by showing his/her baseline heart rate and also any increases in the heart rate due to movement. Just as your heart rate goes up after movement, your baby's heart rate also increases when he/she moves around in the uterus.
This test will also show if you are having any contractions. If you have an NST, you will relax in a reclining position with two sensors (attached by monitoring belts) around your abdomen. One measures your baby's heart rate, while the other measures contractions. You'll be asked to press a button whenever you feel your baby move. This marks the monitor strip so that your baby's movement and heart rate can be compared.
The technician will be looking for a certain number of movements and increases in the heart rate, within a prescribed amount of time. An NST is an easy and painless test that can be done in several different settings, such as our office, a clinic, the hospital, or your home.
A non-stress test may be ordered for the following reasons:
- Report of decreased fetal movement
- Diagnosis of diabetes
- Diagnosis of hypertension or gestational hypertension
- Multiple gestation (twins, triplets, etc.)
- Premature rupture of membrane
- After a car accident or other accident
- Post-date pregnancy (beyond 42 weeks gestation)
NSTs can be started as early as 27 to 28 weeks, with the majority being done after 32 weeks gestation.
There may be only one test ordered, or they may be repeated several times. If the results of your NST are unclear or unsatisfactory, a biophysical profile may be requested. This test combines an NST and ultrasound to determine the baby's heart rate, movement, muscle tone, breathing movements, and the amount of amniotic fluid.