Basic Fetal Monitoring
Southwest Washington Perinatal
Education Consortium
Kathleen Murray,
CNM, MN, RN
Objectives
• Identify the components of a fetal heart rate
pattern: baseline, variability, accelerations,
decelerations, periodic, and non-periodic
changes
• Discuss maternal and fetal physiology and
how it influences fetal heart rate patterns
• Differentiate criteria for reassuring and nonreassuring fetal heart rate patterns
Fetal Heart Rate Monitoring
Techniques
• Auscultation
• Fetoscope
Auscultation
• Fetoscope
Low tech
Need quiet room
Auscultation
• Doppler
Motion detector
Portable
Some models are
made for underwater
use (in tub)
Doppler
Doppler used throughout
pregnancy and labor
Auscultation Benefits
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Detects baseline
FHR rhythm and dysrhythmias
Hear changes in fetal heart rate
Differentiates maternal from fetal heart rate
Auscultation Limitations
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Not continuous
No printout or computer record
Can’t demonstrate variability
Requires some 1:1 nurse-time
May be limited by position of mother
Fetal Heart Rate Monitoring
Techniques
• Electronic Fetal Monitoring
External
Internal
Fetal Monitoring Strip
What’s the
Purpose
of
Fetal Monitoring???
Purpose of Electronic
Fetal Monitoring
• Identify reassuring signs of fetal well-being
• Screen for non-reassuring signs of a fetus
who is at risk
Benefits of External Fetal
Monitoring (EFM)
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Noninvasive
Paper document
Demonstrates variability
Less labor intensive
Limitations of EFM
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Restricts patient movement
Measures cardiac motion, is not ECG
Doubling or half-count of FHR possible
Might pick up maternal HR instead
Internal Fetal Monitoring
• Spiral electrode (FSE) provides direct ECG
• Measures interval between R waves
• Produces very accurate picture of FHR
Benefits of Internal Monitoring
(Using FSE)
• Accurate measure of FHR and variability
• May detect dysrhythmias
• Can allow for more patient movement
Limitations of FSE
• Membranes must be ruptured to use
• Risk of infection
• If fetus has died, may pick up maternal
heart rate accidentally
Uterine Activity Monitoring
• External: tocotransducer
• Detects frequency and length, not strength
• Requires palpation to assess strength of
contractions
Uterine Monitoring
• Note the normallooking UC first
• Then baseline rises
and next few UC’s
seem high (false)
• External UC monitor
does not accurately
show strength
External Uterine Monitoring
• BENEFITS
• Noninvasive
• Provides
documentation of UC
frequency and
duration
• LIMITATIONS
• Does not measure
strength of
contraction, nor
resting tone of uterus
• Difficult to use in
maternal obesity, in
some positions
Monitoring With Internal Uterine
Pressure Catheter (IUPC)
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Accurate measure of uterine pressure
Contraction strength, and resting tone
Measured in mmHg
Accurate timing of FHR changes in relation
to UC’s
IUPC
• INDICATIONS
• External reading not
adequate
• Labor dystocia
• Fetal distress
• Amnioinfusion for
cord compression
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RISKS
Infection
Uterine perforation
Placental injury
Extraovular placement
IUPC placement
Are You
Worried?
Fetal Heart Rate Monitoring
• Baseline, rounded up to nearest 5 bpm
• Variability
• Accels and Decels
•
Periodic changes (with UC’s)
•
Non-periodic changes (spontaneous)
Fetal Heart Rate Monitoring
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Baseline
Normal: 110-160 bpm
Tachycardia : >160 bpm for >10 minutes
Bradycardia: <110 bpm for >10 minutes
Variability
• Characteristic of FHR baseline
• Smoothness, or roughness of the line
• Very important characteristic of FHR, must
be present for reassuring strip
Variability
• Assessed in between UC’s and periodic
changes
• Absent: undetectable
• Minimal: 1-5 bpm amplitude
• Moderate: 6-25 bpm (normal)
• Marked: >25 bpm (also called saltatory)
Causes of Decreased Variability
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Non hypoxic causes
Fetal sleep (20 min)
Medications
Tachycardia (such as
from maternal fever)
• Fetal anomaly
• dysrhythmia
• Hypoxic causes
• Uteroplacental
insufficiency
• Cord compression
• Mat. Hypotension
• Tachysystole
• Abruption
• Tachycardia
Interventions
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Determine cause
Position change
IV fluids
Oxygen 10 liters snug face mask
Stop or turn down pitocin
Place internal FSE
Notify MD/CNM without delay
Sinusoidal Pattern
• Not to be confused with variability!!
• Regular, sine-like wave pattern with amplitude of
5-15 bpm above and below baseline
• Ominous in most cases, requires prompt
intervention, usually immediate C-section
• Usually caused by severe fetal anemia, can be
from hypoxia, or briefly from narcotic dose
Causes of Increased Variability
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Uteroplacental insufficiency or
Cord Compression or
Fetal Activity and
A compensatory response to a mild hypoxic
event
Interventions
• Determine cause
• Position change
• Assess fetal response
Accelerations
• Caused by sympathetic nervous system
response to fetal movement or stimuli,
normal and reassuring, rules out acidosis
• But, periodic accels, with UC’s are mild
cord compression
Criteria for Accelerations
• <32 weeks gestation, stays 10 beats above
baseline for at least 10 seconds
• For > 32 weeks, acceleration stays 15 beats
above baseline for at least 15 seconds
Early Decelerations
• Caused by pressure on fetal head, vagal
response
• Uniform, mirrors contraction
• Gradual onset, reaches nadir >30 sec.
• Reaches nadir at peak of UC, returns to
baseline by the end of UC
• Benign
Variable Decelerations
• Caused by cord compression, baroceptor
response quickly slows FHR to compensate
• Abrupt onset, reaches nadir < 30 sec.
• Decel. Of >15 bpm lasting > 15 sec., and
return to baseline < 2 minutes
Causes of Variable Decelerations
• Intrauterine
• Nuchal cord, or body
entanglement
• Oligohydramnios
• Rupture of membranes
• Short cord or true knot
• Occult prolapse of
cord
• Maternal conditions
• Positioning
• Second stage labor
with descent
• Monoamniotic
multiple gestation
Variable Decel. Characteristics
• Shape, depth, and duration vary (not
uniform), can be V, W, U shaped
• Timing may vary
• Watch for fetal compromise
• increasing baseline
• loss of variability
• slow return to baseline
Interventions
• Vag. Exam rule out
prolapse
• Position change
• IV fluids
• Oxygen 10 l/mask
• Turn pit off or down
• Assess fetal response
• Call MD/CNM
• Same list as with late
decels, except added
vag exam, and
• If ordered, start
amnioinfusion
Late Decelerations
• Caused by uteroplacental insufficiency
• Fetus runs low on oxygen during a UC
• Maternal, placental, or fetal cause of
inadequate oxygen to fetal heart
• Often indicates metabolic acidosis
• Needs urgent response
Late Decel. Characteristics
• Always associated with a UC, with delay in
timing
• Gradual decrease from baseline to nadir >30
seconds
• Nadir occurs after peak of UC
• Depth of decel usually only 5-30 bpm
Interventions
• Lateral position,
(usually left works
best)
• Increase IV fluids
• Oxygen 10 l/mask
• Stop pitocin
• Call MD/CNM
• Determine cause, and
correct if possible
• Assess fetal response
• Prepare for possible
delivery
Prolonged deceleration
• Deceleration of >15bpm, lasting more than
2 minutes, less than 10 minutes
• Measured from onset until return to baseline
• Often is long, exaggerated variable
• Cause often: cord compression, or
tachysystole, or maternal hypotension
Interventions
Without Looking at Your Notes, Tell
Me What You’d Do for a Prolonged
Decel?
Hint: Same List As for lates
Interventions
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Lateral position
Increase IV fluids
Oxygen 10 l/mask
Stop pitocin
Call MD/CNM
• Determine cause, and
correct
• Assess fetal response
• Prepare for possible
delivery, moving into
O.R. by 3rd minute if
not resolving
Uterine Contractions
Contraction Monitoring
• Interval “how far apart are they?”
• Duration “how long do they last?”
• Resting tone: how does the uterus feel between
contractions
• Intensity “how hard are they?”
mild
moderate
strong
Electronic Fetal Monitoring
Strip Interpretation
Systematic Review of strip
• Baseline
Normal is ___________
• Variability
Expressed as _________
• Accelerations
Present, or absent
• Decelerations
Present, or absent
3 major types:
________________
________________
________________
• Contraction pattern
Begin….
• By looking at what is
reassuring on the strip
• Then, note any
concerning features
Documentation
• Critical job for you, your hospital, the
patient
• Chart as if the hard copy of your strip will
get lost later…10% or more of all strips do
• Clear, concise language
• Institution-specific
• Standards of care
Documentation on the strip
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Label/write patient name, date etc.
Events, actions, nursing interventions
Calls to MD, CNM, nursery, etc.
What not to write on strip
Auscultation documentation
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Rate
Rhythm (regular, irregular)
Increases in rate (audible accels)
Decreases (audible decels, and the timing)
FHR Documentation Intervals
Auscultation or EFM
• Low risk patient:
Active labor every 30 minutes
2nd stage every 15 minutes
• High risk patient
Active labor every 15 minutes
2nd stage every 5 minutes
If Confusing Pattern
• Complex patterns, combination of 2 types
of decelerations sometimes exist
• Focus on: baseline stable or not, variability
and accels, whether decels are periodic or
not, timing related to UC’s, abruptness of
change from baseline
• Sometimes helps to draw decel in your chart
notes
Documenting Uterine Activity
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What four characteristics do you note?
____________________
____________________
____________________
____________________
Example of Charting
2100-FHR baseline 130, accels to 160
present, no decels. UC’s q 2.5 minutes x
60-80 seconds, palpate moderate, resting
tone soft.
K Jones, RN
Non-reassuring FHR Patterns
• Document the following:
Pattern
Nursing intervention
Evaluation of response
Notification of MD or CNM
Example of Charting
• 2120- FHR 170, minimal variability, no accels, no
decels. UC’s q 2.5-3 minutes x 80-130 seconds,
peaks 40-50mmHg, resting tone 25.
• Positioned Left-lateral, O2 on 10 l per tight
mask, pitocin turned off, IV rate increased. No
change in FHR pattern. Phoned Dr James with
report of non-reassuring strip and asked him to
come now to evaluate. He stated he is on his way.
Explained to patient and husband. K Jones, RN
Conclusion
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Methods of fetal monitoring
Components of FHR, and uterine activity
Causes of various changes
Nursing interventions
Systematic review of strip
Documentation
References
Abcdefm:electronic fetal monitoring , Curran, Carol,
and Torgersen, Keiko, Colley Avenue Copies &
Graphics, Virginia Beach, VA, 2006, pp.31,158-9,
167,169,170,178-9.
Fetal Heart Monitoring Principles & Practices 4th
ed., Lyndon, Audrey et al editors, AWHONN,
Kendall/Hunt, Dubuque, Iowa, 2003.
NCC Monograph, Vol 2, No. 1, 2006, National
Certification Corporation, pages 6-11.