Fetal Heart Rate Monitoring

Question 1

When looking at a FHR tracing and trying to determine the baseline heart rate, what areas on the graph are ignored?

Answer 1

Anything where there is a drop or rise in the heart rate by 25 bpm or more. In other words, when there is craziness happening and deviation from the baseline.

Question 2

What are the components of a FHR tracing that we care about, in order?

Answer 2

-Baseline heart rate
-Degree of variability
-Presence and frequency of accelerations vs decelerations (early vs late vs variable)
-Frequency of Contractions

Question 3

What are baseline changes in the FHR tracing?

Answer 3

Changes in the baseline heart rate for ten minutes (entire strip) or more.

Question 4

What is the cut off for tachycardia and bradycardia to a fetus during FHR monitoring?

Answer 4

Bradycardia: <110 bpm
Tachycardia: over 160 bpm

Question 5

What range of bradycardia is okay for a fetus?

Answer 5

100-110 is okay for a fetus, so long as this is an isolated finding.

Question 6

What typically causes bradycardia in a fetus?

Answer 6

Heart block (no variability)

Question 7

When is a little bit of tachycardia okay for a fetus?

Answer 7

Tachycardia not above 170 is okay if there is moderate or marked variability.

Question 8

What typically causes tachycardia in a fetus?

Answer 8

Maternal infection, mild fetal anemia, fetal heart failure, fetal hypoxia, beta sympathomimetics (Albuterol?)

Question 9

Besides bradycardia, what sign tells us that a fetus has a heart block?

Answer 9

When a low baseline HR is coupled with little to no variability.

Question 10

What are the cutoffs for the different types of variability?

Answer 10

-minimal: under 5 bpm
-moderate: 6-25 bpm ✅
-marked: over 25 bpm ✅

Question 11

What is the variability of a sinusoidal wave pattern on a FHR tracing?

Answer 11

There is no/minimal variability for a sinusoidal pattern.

Question 12

What does the sinusoidal wave pattern mean on a FHR tracing?

Answer 12

It tells us that there is severe fetal anemia! We need to deliver that baby soon.

Question 13

If the fetal heart rate is normal, but the variability changed from moderate to minimal, what could be going on? Is there cause for alarm?

Answer 13

The baby could be having a sleep cycle.

No cause for alarm :/
Only worry if there is bradycardia too. (Sign of heart block)

Question 14

What is an adequate acceleration? What age of gestation determines that?

How frequent must they occur?

What is a prolonged acceleration?

Answer 14

-Raise in FHR over 10 bpm or 15 bpm, if under or over 32 weeks, respectively. They must go from baseline to peak before 30 seconds. The entire thing (from baseline to baseline) must not exceed 2 minutes (2 big boxes).

-at least 2 in 20 minutes to be considered actual accelerations.

-A prolonged acceleration is an acceleration that lasts longer than 2 minutes but does not exceed 10 minutes.

Question 15

When do we add fetal scalp stimulation?

What happens when the fetus does not respond to fetal scalp stimulation?

Answer 15

When there has not been a single acceleration for an hour and 20 minutes.

There is a higher rate of mortality, and there is probably acidosis going on if the fetus does not respond to fetal scalp stimulation.

Question 16

What does fetal scalp stimulation do?

Answer 16

It causes the baby to do something which causes an acceleration.

Question 17

Decreased or no variability is a reliable sign of what?

Answer 17

Fetal acidosis.

Question 18

Describe the waveform of an early deceleration?

Describe the waveform of a late deceleration?

Answer 18

-Early decelerations usually take over 30 seconds (3 small boxes) to go from baseline to nadir (trough/lowest point). Their nadir usually occurs on top on the peak of a contraction.

-Late decelerations take over 30 seconds from base to nadir, too. Their nadir occurs after the peak of a contraction, though.

Question 19

Describe the waveform of a variable contraction.

Answer 19

A variable contraction takes less than 30 seconds to go from base to nadir and then has an abrupt recovery to baseline (looks like a “v”).

Question 20

What do late decelerations mean?

Answer 20

Late decelerations indicate that the fetus is not getting good oxygenated blood.
-maternal hypotension
-maternal hypoxemia
-excessive uterine contractions
-placental abruption

Question 21

What maneuvers and non-invasive things can we do to manage recurrent (greater than 50% of contractions) late decelerations?

Answer 21

-Reposition mom on her left side (to allow IVC on the right side of spine some room to breath and increase venous return to the heart).
-give O2 through a tight face mask.
-Stop any oxytocin/pitocon.
-Correct maternal hypotension/give IVF fluids.

Question 22

If the maneuvers for correcting late decelerations don’t work and 30 minutes passed by, what is the next step?

Answer 22

Get fetal scalp pH reading on the baby.
-over 7.25 is good
-7.2 till 7.25 is okay. Repeat in 30 minutes.
-under 7.2, immediately deliver this baby.

Question 23

If we see recurrent late decelerations and no variability, what should we do next?

Answer 23

Deliver the fudge out of that baby and it’s mom.

Question 24

What two things cause variable decelerations?

Answer 24

Fetal head compression and complete occlusion of the umbilical cord.

Question 25

How do we manage variable decelerations?

Answer 25

-Vaginal exam to see if the fetal head is through or if the cord is prolapsed. -Trendelendberg to relieve weight on the cord. -Consider amnioinfusion if index is low. -Stop oxytocin. -Give O2 through a tight face mask.

Question 26

How often should someone have uterine contractions?

Answer 26

5 every ten minutes. In other words, 1 every two minutes.

Question 27

What is the tachysystole of the uterus?

Answer 27

When there contractions are happening more than 5 times in 10 minutes (they are too frequent)!

Question 28

If a PT is having recurrent late decelerations and 8 contractions over a FHR strip, what should we do?

Answer 28

Give Terbutaline to stop the contractions in their tracks.

Question 29

What is a category I FHR tracing?

Answer 29

It is when they have FHR 110-160, moderate variability, and no late or variable decelerations.

Question 30

What is a category III FHR tracing? What should we do in the case of a category III FHR tracing?

Answer 30

A wave form on the FHR tracing showing: -a sinusoidal pattern -recurrent late decelerations w/no variability -recurrent variable decelerations -bradycardia We need to deliver that baby immediately.

Question 31

If a pregnant PT has DKA or pneumonia with hypoxia, and her FHR tracing shows recurrent late decelerations with no variability, what should we do?

Answer 31

Treat their condition. Do not deliver the baby even though the FHR tracing is category 3. The minimal variability is from the mother's acidosis or hypoxia and not the baby itself. Therefore, treating mom's condition will cause the FHR tracing to improve.