Fetal Heart Rate Monitoring

Question 1

What contraction variables can be accurately measured by a pressure sensitive tocodynanmometer?

Answer 1

Registering the frequency of contractions, NOT the strength (external monitoring)

Question 2

At what point are the mother and baby physiologically separated from each other?

Answer 2

With each contraction, for a few seconds (blood flow initially ceases when vessels are compressed)

Question 3

What is the normal rate of uterine contraction?

Answer 3

5 contractions or less in 10 mins (avg over 30 mins)

Question 4

What is tachysystole?

Answer 4

> 5 contractions in 10 mins (avg over 30 mins)

Question 5

What is the mean FHR baseline? What would be considered tachycardia and bradycardia?

Answer 5

Normal= 110-160 bpm
Tachycardia: baseline >160
Bradycardia: baseline

Question 6

What is the most common cause of fetal tachycardia?

Answer 6

Fetal infection (chorioamnionitis)

Question 7

What is the normal variability of the baseline amplitude range of FHR?

Answer 7

amplitude of 6-25bpm (Moderate variability)

Question 8

What causes early decelerations?

Answer 8

Head compression (normal, will be mirror image of contraction)

Question 9

What causes variable decelerations? When would they be worrisome?

Answer 9

Umbilical cord compression (shoulder, deep V)

Worry if they are recurrent (>50% of contractions)

Question 10

What causes late decelerations? What do they indicate if they are repetitive?

Answer 10

Uterine placental insufficiency (ominous)

Repetitive- Indicate low fetal pH and metabolic acidosis

Question 11

What does a sinusoidal pattern indicate in FHR?

Answer 11

Fetal anemia

Question 12

What is a normal reactive NST?

Answer 12

15bpm above baseline lasting 15 seconds, twice within a 20 minute period