Fetal Heart Tone

Fetal Heart Tone (FHR) should be 120-160 beats per minute throughout the pregnancy. It can be heard as early as 11th week by the use of an ultrasonic doppler technique

Variabilities of Fetal Heart Tone:

a) Decreased Variability - CNS depression (often due to meds)
b) Early Deceleration - not caused by hypoxia nor can result to poor fetal outcome
c) Late Deceleration - a fetal hypoxia and distress due to pre-eclampsia, maternal hypotension, excessive uterine contraction

Assessment of Fetal Heart Tone can be done through:

1. Rhythm Strip Testing - Fetal Heart Tone is assessed in terms of baseline and long-and-short term variability.
- baseline reading means the average rate of the fetal heart beat per minute
- short term variability denotes the small changes in rate that occur from second to second
- long term variability denotes the difference in heart rate that occurs over a 10 or 20 minute time period

2. Non-Stress Testing
- done in 10 minutes to note the response of FHR to fetal movement
- as fetus moves, FHR should be increased by 15 beats per minute and remain elevated for 15 seconds, then return to its pattern as the fetus quiets
- the test is reactive if 2 accelerations of fetal heart rate lasting for 15 seconds occur following movement within 10 minutes period.
- the test is non-reactive if no accelerations occur with fetal movements. Amniocentesis is indicated to check lung maturity
- if 10 minute period passed without fetal movement, it means that the fetus is sleeping. Give the mother oral carbohydrate snack to increase the glucose level and stimulate fetal movement.

3. Vibroacoustic Stimulation
- the application of an instrument to produce a sharp sound to the mother's abdomen to startle and wake the fetus.

Enter your email address:

Delivered by FeedBurner