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Fetal Heart Tone Sinusoidal Pattern

Aka: Fetal Heart Tone Sinusoidal Pattern, FHT Sinusoidal Pattern, FHR Sinusoidal Pattern, FHR Pseudo-sinusoidal Pattern

See Also
Definition
1. Smooth undulating sine wave pattern
2. Amplitude: 10 to 15 bpm
3. Frequency: 3-5 cycles per minute
4. Duration: >2 minutes
Causes
1. Ominous sign
  1. May represent terminal rhythm
  2. Requires immediate evaluation
2. Severe fetal Anemia (e.g. Fetal hydrops)
3. Maternal medications or Illicit Drugs
Differential Diagnosis
1. Pseudo-sinusoidal FHR pattern
  1. Appears similar to sinusoidal pattern
  2. Short-term variability present
  3. Benign finding
References
1. Bailey (2000) ALSO, E:1-13
2. Gabbe (2002) Obstetrics, p. 395
3. Rylander (2001) Clin Fam Pract 3(2):287-305

Family Practice Notebook

Patients should address specific medical concerns with their physicians.

Although access to this page is not restricted, the information found here is intended for use by medical providers.

This page was written by Scott Moses, MD, last revised on 10/21/2007 and last published on 5/14/2013.

This is one of 5887 pages in the Family Practice Notebook