1. Fetal Heart Rate Monitoring
Paul G. Tomich, M.D.
Department of Obstetrics and Gynecology
University of Nebraska College of Medicine

2. Learning Objectives Evolution Examples Descriptions
Reassuring patterns
Concerning patterns
Definitions of Category I, II, and III tracings
Discuss action needed
Non-stress Test (NST)
Biophysical Profile (BPP)

3. “Evolution” of FHR Monitoring
Monitoring fetus in labor
FHR patterns
Good outcomes
Poor outcomes
Contraction Stress Test (CST)
Non Stress Test (NST)
Biophysical profile (BPP)
Categorization of FHR Tracing into Category I, II, and III

4. Categorization of FHR Tracings
Recommendation of three-tiered system
April 2008
More standardized interpretation
Concept: Interpretation of a FHR monitor strip is a dynamic process, with determination of whether a particular strip is reassuring and what action plans should be taken… and then to evaluate at a later time

5. Ways to Monitor
Uterine contractions
Fetal heart rate (FHR)

6. Ways to Monitor
Uterine contractions
Fetal heart rate (FHR)

7. Features to Describe Fetal heart rate (FHR) Uterine contractions
Top line on monitor strip
Uterine contractions
Bottom line on
monitor strip

8. Features to Describe Baseline Variability Accelerations Decelerations
Trends over time
Interpret into 1 of 3 categories

9. Baseline Mean fetal heart rate Normal baseline
Rounded to increments of 5
During a 10 minute period
Excluding accelerations and decelerations
Normal baseline
BPM

10. Baseline is RED LINE

11. Baseline Bradycardia Tachycardia Indeterminate <100 BPM >160 BPM
less than 2 minutes of baseline is present

13. Fetal Tachycardia Normal variant Intra-amniotic infection Fetal anemia
prematurity
Intra-amniotic infection
Fetal anemia
Fetal cardiac arrhythmia (SVT)
Fetal hypoxia

14. Features to Describe Baseline Variability Accelerations Decelerations
Trends over time
Interpret into 1 of 3 categories

15. Variability Fluctuations in FHR Descriptors are: Over 10 minutes
Absent: undetectable amplitude range
Minimal: undetectable up to 5 BPM
Moderate: amplitude range 6 to 25 BPM
Marked: amplitude range greater than 25 BPM

17. Variability

20. Features to Describe Baseline Variability Accelerations Decelerations
Trends over time
Interpret into 1 of 3 categories

21. Accelerations Abrupt increase in FHR Duration Prolonged accelerations
At least 15 BPM above baseline
Duration
Must last 15 seconds to 2 minutes
Prolonged accelerations
Last 2 minutes to 10 minutes
Baseline change
Acceleration lasting 10 mins or longer

22. >15 beats above baseline
15 seconds to 2 minutes in length

25. Features to Describe Decelerations Baseline Variability Accelerations
Trends over time
Interpret into 1 of 3 categories

26. Decelerations
Decrease in baseline
3 Types
Early
Variable
Late

27. Deceleration
Decrease in FHR

28. Early Deceleration Symmetrical to contraction
Mirror image of contraction
Gradual decrease in FHR
30 secs or more from onset to nadir

29. EARLY DECELERATION Gradual FHR decrease
Onset to nadir 30 seconds or more
Nadir of deceleration occurs with peak of contraction
Mirror contraction

30. Late Decelerations Deceleration is delayed in timing
Occurs after the contraction
A gradual FHR decrease
Onset to nadir > 30 second

31. Late Decelerations

32. Variable Decelerations
Abrupt decrease in fetal heart rate
Onset to nadir less than 30 seconds
Decrease in FHR
15 BPM or more
Lasting 15 seconds to 2 mins

33. Variable Declerations
Pathophysiology
umbilical cord compression

37. Decelerations Prolonged deceleration Baseline change Description
Decrease of 15 BPM
Lasts minutes
Baseline change
Deceleration lasting at least 10 mins
Description
Intermittent
Less than 50% of contractions in 20 minutes
Recurrent
More than 50 % of contractions in 20 minutes

43. Sinusoidal Pattern Smooth sin-wave pattern Cycle frequency 3-5 mins
Persists for 20 minutes or longer

44. Sinusoidal Pattern

45. Uterine Contractions Number of contractions in 10 minutes Document
averaged over thirty minutes
Document
Frequency
Intensity
Duration
Relaxation
time between contractions

46. Monitoring of Contractions

48. Tachysystole
>5 contractions in 10 mins
Averaged over 30 mins

49. Categorization of FHR Patterns
An evaluation of the fetus at a particular point in time
Categories I, II, and III

50. 3 Categories

51. Category I Normal baseline FHR Variability
BPM
FHR Variability
moderate
Late or Variable decelerations
none

52. Category II
Not enough evidence to place into either Category I or III

53. Category III Abnormal tracing
Predictive of abnormal fetal acid-base status
Requires prompt intervention

54. The ABCD’s of Fetal Monitoring

55. Examples of Tracings

56. Minimal to moderate variability
Baseline 140
earlies

58. Baseline rate 150
Baseline variability (min, avg. marked) min
Presence of accelerations none
Periodic or episodic decelerations: lates
Uterine activity q 3 (2 contx)
Interventions: maximize O2, maximize uterine blood flow, reduce uterine activity
Outcome: not given

59. Late deceleration
Minimal variability

60. Late deceleration
Minimal variability

61. Variable decelerations
Mod variability

63. Non-Stress Test Reactive 2 or more accelerations in 20 mins
At least 15 beats above baseline
Lasting for at least 15 seconds
Non-reactive

65. Reactive NST

66. Biophysical Profile (BPP)
NST + ultrasound markers
Score linearly correlated with fetal pH
Risk of fetal death within one week of normal BPP is 1:1300

67. Biophysical Profile Zero or 2 points for each
Fetal heart beat monitor
Fetal breathing
Fetal movements
Amniotic Fluid Volume
Flexion/Extension
Fetal Monitoring accelerations in 40 minutes
Fetal Breathing seconds
Fetal Movements Truncal
Flexion/Extension Arm/leg activity
Amniotic Fluid AFI > 5.0 cm
BPP of 8/10 or 10/10 is “normal” or “reassuring”
BPP of 6/10 requires some sort of intervention

68. Modified Biophysical Profile
Combination of NST and AFI only
If less than 4/4
more evaluation is done

69. Guidelines for Reviewing FHR Monitoring
normal patient
reviewed every 30 min in the first stage of labor
every 15 minutes in the second stage
complicated patients
every 15 minutes in first stage
Every 5 mins in second stage