The non-stress test (NST) is a common prenatal test used to evaluate fetal well-being in the third trimester of pregnancy. The test involves continuous electronic monitoring of the fetal heart rate and movements using ultrasound or other sensors. It is a non-invasive test performed when the fetus is over 28 weeks of gestation. During the 20-40 minute test, accelerations in the fetal heart rate in response to movement are evaluated to determine if the fetus is reactive and healthy or non-reactive, which may require further evaluation. The test helps assess fetal oxygen levels and growth without placing stress on the fetus.

1. NON STRESS TEST
PRESENTED BY
PREETI SHUKLA
LECTURER, RCN
KANPUR

4. Don't worry - it's not stressful. The non stress test
is a third trimester check of only your baby's well-
being………

5. INTRODUCTION
The Fetal Non-Stress test is a simple, non-
invasive test.
performed in pregnancies over 28 weeks
gestation.
The test is named “non-stress” because no
stress is placed on the fetus during the test.

6. DEFINITION
It is a continuous electronic fetal monitoring of Fetal
heart rate with recording of fetal movement in
cardiotocography and wellness of fetus.
OR
Prenatal non-stress test, popularly known as NST, is
a method used to test fetal wellbeing before the onset
of labor.

7. PURPOSE OF NON STRESS TEST
Assessment of fetal wellbeing.
To evaluate the ability of fetal heart rate to
accelerate.
To know oxygen supply to fetus.
To know the need of further monitoring and
testing.

8. INDICATION FOR NON STRESS
TEST
 Gestational Diabetes mellitus.
 High blood pressure, or some other medical condition that
could affect pregnancy.
 Gestational hypertension.
 Baby appears to be small or not growing properly.
 Baby is less active than normal.

9.  Have too much or too little amniotic fluid.
 Patient had a procedure such as an external cephalic
version (to turn a breech baby).
 Third trimester after amniocentesis.
 To see how baby is holding up during his extended
stay in the womb.

10. • Previously lost a baby in the second half of
pregnancy, for an unknown reason.
• Medical problem that may jeopardize the baby's
health.
• If the baby has been diagnosed with an abnormality
or birth defect and needs to be monitored.

11. • Sense that the baby is not moving as frequently as
usual.
• Overdue date.
• There is any reason to suspect that the placenta is
not functioning adequately.
• High risk for any other reason.

12. WHEN TO NST PERFORMED??
 NSTs are generally performed after 28 weeks of
gestation.
 Before 28 weeks, the fetus is not developed enough to
respond to the test protocol.

13. EQUIPMENTS
• Non stress test machine
• A tray containing- Abdominal binding belt
• Stethoscope to evaluate the location of FHR.
• Jelly and cotton pad
• Graph paper
• Doppler (ultra) transducer for fetal heart rate
monitoring
• Pressure (toco) transducer for monitoring of
uterine contractions and fetal movement.
• Event marker for monitoring fetal movement.

16. PROCEDURE
• Before the examination ask to mother for having
some food or not.
• Advice to mother for voiding, it will prevent the
interruption between the procedure.
• Explain the procedure to mother.
• Make the patient sit in a chair or lean back on a exam
table or bed.

17. • Fastened onto it are two monitors, one to pick up the
baby's heart rate; the other senses uterine
contractions.
• Allow the patient to hold a event marker and explain
to click each time she feel the baby move.
• The monitoring goes on for 20 to 40 minutes.

18. • A baby who moves a lot and has a normal heart rate is
classified as "reactive.“
• He is considered healthy
• A "nonreactive" baby is not necessarily in danger; the
baby could just be asleep.

19. INTERPRETATIONS
Reactive
At least two FHR acceleration with or
without fetal movement occurring within 20
minutes period and peak in at least 15 bpm
above the baseline and lasting 15 seconds from
baseline to baseline.

21. Non reactive
Absence of fetal activity, or no acceleration
or no acceleration for 15 bpm or acceleration
for less than 15seconds in duration for 40
minutes period.

22. Advantages
It is non invasive procedure.
Painless procedure.
No risk for fetus and mother.
It is easy to administer weekly or daily.
Results are available readily.

23. DISADVANTAGES
False the result often occur since Various method
have been used to stimulate fetus to elicit
acceleration in fetal heart rate.

24. References
• American College of Obstetricians and Gynecologists (ACOG).
(1999). Antepartum fetal surveillance (Practice Bulletin No. 9).
Washington, DC: Author.
• Association of Women’s Health, Obstetric, and Neonatal Nurses
(2005). Audrey Lyndon, Linda Usher Ali. ed. Fetal Heart Monitoring:
Principles and Practices (3rd ed.). Dubuque, IA: Kendall/Hunt
Publishing Co. ISBN 978-0-7575-6234-1.
• Lagrew, D. C., Jr. (1995). The contraction stress test. Clinical
Obstetrics and Gynecology, 38(1), 11–25.
• Ray M, Freeman R, Pine S, Hesselgesser R (September 1972).
"Clinical experience with the oxytocin challenge test". Am. J. Obstet.
Gynecol. 114 (1): 1–9. PMID 4637035.