20: Fetal Heart Monitoring

Question 1

How often should you be intermittently monitoring a patient if pregnancy if uncomplicated?

Answer 1

q30 min in active phase of 1st stage of labor

q15 min in 2nd stage of labor

Question 2

How often should you be intermittently monitoring a patient if pregnancy is complicated?

Answer 2

q15 min in active phase of 1st stage of labor

q5 min during 2nd stage

Question 3

Which type of monitoring will provide more accurate tracings?

Answer 3

Internal monitoring

Question 4

What is the normal pH of fetal scalp blood?

Answer 4

7.25-7.30

Question 5

When is the pH of fetal scalp blood considered abnormal (fetal acidosis)?

Answer 5

pH < 7.20

Question 6

What does the upper tracing in a fetal monitoring strip show?

Answer 6

FHR

Question 7

What does the lower tracing in a fetal monitoring strip show?

Answer 7

Uterine contraction

Question 8

Normal uterine activity

Answer 8

5 contractions in 10 minutes, averaged over a 30 minute window

Question 9

Tachysystole

Answer 9

More than 5 contractions in 10 minutes averaged over a 30 minute window

Question 10

Normal contractions

Answer 10

3 contractions in 8 minutes; contractions occurring every 2-3 minutes

Question 11

MVUs

Answer 11

Montevideo units (measured by IUPC); the sum of contractions in a 10 minute period; need greater than 200 for at least 2 hours

Question 12

Baseline FHR

Answer 12

Mean FHR rounded to increments of 5 bpm during a 10 minute segment. Assessed between contractions

Question 13

Normal FHR baseline

Answer 13

110-160 bpm

Question 14

Tachycardia FHR baseline

Answer 14

Greater than 160 bpm

Question 15

Bradycardia FHR baseline

Answer 15

Less than 110 bpm

Question 16

Most common cause of fetal tachycardhia

Answer 16

CHORIOAMNIONITIS/fetal infection

Question 17

Baseline Variability

Answer 17

Amplitude of the peak-to-trough in bpm of change in baseline rate

Question 18

Absent variability

Answer 18

Amplitude range undetected

Question 19

Minimal variability

Answer 19

Amplitude range detectable but less than or equal to 5 bpm

Question 20

Moderate (normal) variability

Answer 20

Amplitude range 6-25 bpm

Question 21

Marked variability

Answer 21

Amplitude range greater than 25 bpm

Question 22

Decreased variability

Answer 22

Can indicate possible fetal stress, especially ominous with late persistent decelerations; associated with hypoxia and acidemia

Question 23

Accelerations

Answer 23

Abrupt increase in FHR and NORMAL

Question 24

Non-reactive Stress Test

Answer 24

Heart rate of 15 or more bpm above baseline for 15 sec or more (but less than 2 minutes)

Question 25

Prolonged accelerations

Answer 25

Last 2 minutes or longer

Question 26

Deceleration

Answer 26

FHR decreases in response to uterine contractions

Question 27

Early decelerations

Answer 27

GOOD - secondary to head compression; nadir of deceleration occurs at same time as peak of contraction causing a “mirror” image on monitoring strip

Question 28

Variable decelerations

Answer 28

Secondary to umbilical cord compression; abrupt decrease in FHR that can occur at anytime on monitoring strip
Decrease more than 15 bpm lasting 15 sec-2 minutes

Question 29

“Shoulder” phenomenon

Answer 29

When slight increase in FHR is followed by major drop in FHR

Question 30

Late decelerations

Answer 30

BAD - Caused by uterine placental insufficiency. Most ominous deceleration - indicates fetal metabolic acidosis and low arterial pH; Nadir of deceleration occurs after the peak of the contraction

Question 31

Prolonged decelerations

Answer 31

Decrease in FHR from baseline that is more than 15 bpm lasting over 2 minutes but less than 10 minutes; commonly seen during maternal pushing

Question 32

Sinusoidal pattern

Answer 32

Smooth sine wave like pattern in FHR with 3-5 cycles per minute; NOT good - associated with fetal anemia

Question 33

Baseline 110-160 bpm, moderate variablity, no late/variable decelerations

Answer 33

Category I

Question 34

Intermittent variable decelerations or recurrent decelerations; tachysystole

Answer 34

Category II

Question 35

Absent baseline variability, recurrent late decels, recurrent variable decels, bradycardia, sinusoidal pattern

Answer 35

Category III