Nonstress test

Nonstress test
Diagnostics
ICD-9-CM 75.34

A nonstress test (NST) is a screening test used in pregnancy. A cardiotocograph is used to monitor the fetal heart rate.[1]

Premise

The premise of the NST is that a well-oxygenated, non-acidemic fetus will spontaneously have temporary increases in the fetal heart rate (FHR).[2]

Vibroacoustic stimulation can wake the fetus, and is sometimes used to speed up the test or to facilitate further evaluation of a nonreactive nonstress test.[3]

Interpretation

Classified as normal/atypical/abnormal: "Normal" - baseline heart rate between 110-160 with moderate variability (5-25 interbeat variability) and 2 qualifying accelerations in 20 minutes with no decelerations.

Previous terminology: Reactive/non-reactive: *Reactive (normal) - presence of two or more fetal heart rate accelerations within a 20-minute period, with or without fetal movement discernible by the woman.[4] Accelerations are defined as 15 bpm above baselines for at least 15 seconds if beyond 32 weeks gestation, or 10 bpm for at least 10 seconds if at or below 32 weeks.[5]

See also

References

  1. London, Marcia; Ladewig, Patrica; Ball, Jane; Bindler, Ruth (2007). Maternal & Child Nursing Care. Upper Saddle River, NJ: Prentice Hall.
  2. Smith, C. V.; Nguyen, H. N.; Phelan, J. P.; Paul, R. H. (1986). "Intrapartum assessment of fetal well-being: a comparison of fetal acoustic stimulation with acid-base determinations". Am J Obstet Gynecol 155: 726–728. doi:10.1016/s0002-9378(86)80007-2.
  3. Chervenak, Frank A.; Kurjak, Asim (2006). Textbook of Perinatal Medicine, Second Edition (Two Volumes). Informa Healthcare. ISBN 1-84214-333-6.
  4. 1 2 Association of Women’s Health, Obstetric, and Neonatal Nurses (2005). Lyndon, Audrey Lyndon; Ali, Linda Usher, eds. Fetal Heart Monitoring: Principles and Practices (3rd ed.). Dubuque, IA: Kendall/Hunt Publishing Co. ISBN 978-0-7575-6234-1.
  5. Cousins, L. M.; Poeltler, D. M.; Faron, S.; Catanzarite, V.; Daneshmand, S.; Casele, H. (October 2012). "Nonstress testing at ≤ 32.0 weeks' gestation: a randomized trial comparing different assessment criteria". Am J Obstet Gynecol. (Mosby, Inc.) 207 (4): 311.e1–311.e7. doi:10.1016/j.ajog.2012.06.032. Retrieved 3 July 2013.
This article is issued from Wikipedia - version of the Saturday, April 18, 2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.