Performing a Nonstress Test (NST) is a safe, noninvasive procedure used during pregnancy to assess fetal well-being, particularly the baby’s heart rate response to movement. It’s typically done in the third trimester, especially in high-risk pregnancies or when fetal movement decreases.
Definition
A test that monitors the fetal heart rate (FHR) in response to fetal movements in order to assess the integrity of fetal central nervous system and cardiovascular system.
Purposes for Nonstress Test
- To assess the fetal ability to cope with continuation of a high-risk pregnancy.
- To determine the projected ability of a fetus to withstand the stress of labor.
- To assess the fetal status in women for whom contraction stress test is contraindicated such as previous caesarean section, placenta previa or preterm labor.
Indications (maternal)
- Postdated pregnancy.
- Rh sensitization.
- Maternal age 35 or more.
- Chronic renal disease.
- Hypertension.
- Collagen diseases.
- Sickle cell disease.
- Diabetes.
- Premature rupture of membranes.
- History of stillbirth.
- Trauma.
- Vaginal bleeding in second and third trimester.
Indications(fetal)
- Decreased fetal movement.
- Intrauterine growth retardation (IUGR).
- Fetal evaluation after amniocentesis.
- Oligohydramnios/polyhydramnios.
Articles
- Electronic fetal heart monitor.
- Ultrasound transducer.
- Tocotransducer (tocodynamometer).
- Monitor strip.
- Ultrasound gel.
- Belts to hold the transducers in place.
Procedure
| Nursing actions | Rationale | |
| 1. | Before procedure Explain to mother about the procedure and its purpose and how she has to cooperate. | Reduces anxiety and promotes full cooperation. |
| 2. | Make sure that the woman had eaten food and ask her to empty her urinary bladder. | Promotes comfort during the procedure. |
| 3. | During procedure Turn on the monitor and press the “TEST” button to see that it is working and adjust the paper speed (set at 3 cm per minute). | Setting the paper speed at 3 cm per minute increases the accuracy of interpretation. |
| 4. | Perform an abdominal palpation (Leopold’s maneuver). | Locates the fetal position and awakens the fetus. |
| 5. | Confirm the presence of fetal heart tones with a fetoscope or stethoscope and note the area of maximum intensity. | Ensures that the source of pulse detected by the electronic monitor is the fetal heart tone. |
| 6. | Position the woman in semi-Fowler’s or lateral tilt position and place the monitor belts under her back so that they are flat against her skin. | Supine position compresses maternal blood vessels and causes potential supine hypotension. |
| 7. | Connect the ultrasound transducer and the tocotransducer to the fetal monitor. Apply ultrasound gel to the ultrasound transducer. | Ultrasound gel improves sound conduction. |
| 8. | Place the ultrasound transducer on the fetal back. Move the transducer until clear, audible fetal heart tones are heard and the signal light is flashing steadily. Secure the device in place with belt. | |
| 9. | Place the tocotransducer on the fundus of the uterus and secure in place with the belt. | |
| 10. | Run the monitor and evaluate the quality of the tracing to determine if it is adequate for interpretation. If it is not, reposition the transducer until interpretable data is obtained. | |
| 11. | Give the hand button to the woman and ask her to press the button every time she feels fetal movement. | Serves to monitor the recorded mark at each point of fetal movement, which is used as a reference point to assess FHR response. |
| 12. | Run the monitor and obtain a tracing for at least 20 minutes. | Observes FHR and uterine activity. |
| 13. | On completion, put off the monitor and take out the strip of paper. | For assessment of fetal health. |
| 14. | After procedure Remove the abdominal straps and wipe off the gel from the abdomen and transducer. | Promotes cleanliness and comfort. |
| 15. | Make the woman comfortable and give relevant instructions. | Allays anxiety. |
Nursing Considerations
- Ensure maternal comfort and hydration
- Monitor for uterine contractions or decelerations
- Document baseline FHR, variability, accelerations, and maternal report of fetal movement
- Educate the patient on next steps if results are nonreactive
REFERENCES
- Annamma Jacob, Rekha, Jhadav Sonali Tarachand: Clinical Nursing Procedures: The Art of Nursing Practice, 5th Edition, March 2023, Jaypee Publishers, ISBN-13: 978-9356961845 ISBN-10: 9356961840
- Omayalachi CON, Manual of Nursing Procedures and Practice, Vol 1, 3 Edition 2023, Published by Wolters Kluwer’s, ISBN: 978-9393553294
- Sandra Nettina, Lippincott Manual of Nursing Practice, 11th Edition, January 2019, Published by Wolters Kluwer’s, ISBN-13:978-9388313285
- Annamma Jacob, Manual of Midwifery and Gynaecological Nursing, 4th Edition, 2023, Jaypee Publishers, ISBN: 978-9356961593
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