Fetal Monitoring
Lauren Jansen RN, PhD
Assistant Professor
Wilson School of Nursing
Midwestern State University
(940) 397-4547
lauren.jansen@mwsu.edu
Objectives
Discuss the role of Electronic Fetal Monitoring
(EFM) in obstetrical care
Discuss standards of care and documentation of
EFM
Describe the technology of EFM
Investigate the role of acid/base balance
Identify normal characteristics of fetal heart rates
Plan interventions for non-reassuring patterns
Describe indications for antepartal testing
Interpret various rhythm strips
References
AAP/ACOG (1992). Guidelines for Perinatal Care.
Drukker Medical Themes, (1993). The Fourth Annual
Conference of Electronic Fetal Monitoring: The Art, The
Science, The Future.
Murray.M. (1997). Antepartum and Intrapartum Fetal
Monitoring, 2nd Edition.
Schifrin, B. (1989. Exercises in Fetal Monitoring.
History of Electronic Fetal Monitoring
1958: first reported by Dr. Edward Hon
1967: first clinically useful fetal monitor was created
with phonotransducer
Mid 1970s: monitors were being used in many
hospitals
1984: widespread use of EFM throughout the United
States; C/S rates were rising
Currently: 75% of patients are monitored during
labor
Why Monitor?
Goal of Fetal Monitoring
Prevent Maternal and Fetal Morbidity and
Mortality
Surveillance tool to detect the fetal heart
rate and maternal uterine activity
Assess fetal well being; 99% accurate in
predicting a well oxygenated fetus
Provides a permanent record
Records events that cannot be heard or
measured by auscultation alone
Standards
(Based on AWHONN and ACOG Guidelines)
Monitor FHR and its characteristics at specified intervals by selected methods and
document findings using appropriate technology
Monitor UA patterns using palpation and/or EFM
Apply the spiral electrode (ISE, FSE) and/or intrauterine pressure catheter (IUPC)
in accordance with nurse practice acts, institutional policy, and medical orders
Recognize normal and abnormal FHRs or non-reassuring characteristics and
promptly initiate appropriate nursing interventions
Recognize normal and abnormal uterine activity and intervene accordingly
Perform ongoing intrapartal assessment of comfort level
Perform and assess frequent monitoring of the FHR prior to delivery
Use a systematic approach forr tracing review
Intervene with non-supine positioning, IV bolus of non-glucose solution, O@ per
tight face mask at 8-10 L/min, discontinue oxytocin if indicated, and continue
EFM
Communicate changes promptly informing physician of FHR pattern and
interventions performed. If physician does not agree with nursing assessment, a
policy should be in place to resolve conflict
Guidelines for Monitoring
Guidelines
Low risk
Periodically during the latent phase
Every 30 minutes during the active phase
Every 15 minutes during the second stage
High risk
Every 30 minutes during the latent phase
Every 15 minutes the active phase
Every 5 minutes during the second stage
Charting
Documentation
Purpose of Documentation
Provides evidence of care given
May assist the nurse in the event of litigation
Where and What to Document
Monitor Strip
Identification information (patient name & med#)
Physician or nurse initiated treatment
An event or patient care activity which might affect
the FHR or UA tracing (ie. catheterization, etc)
Never assume the strip stand alone; document in
patient record as well
Patient Record
All information documented on tracing should appear
in patient record
Documentation of fetal heart rate, variability, presence
of accelerations in the heart rate, and decelerations in
the heart rate
Summary of significant events of patient care
Use late entry when adding information after the
fact; never backdate, tamper with, or add to notes that
were previously written
Special Issues
Fetal Heart Rate
Variability
Document in terms of terms of variability such as absent, minimal,
average or exaggerated
Acceleration in fetal heart rate
Fetal heart rate patterns
Document baseline as a range (120s, 130s, etc)
Uterine activity assessments (frequency, duration, intensity if palpated)
Describe fetal heart rate deviations with contraction or movement.
Describe decelerations in detail (ex: deceleration of fetal heart rate to
100s from baseline of 150s beginning at the peak of the contraction and
returning to baseline heart rate 30 seconds after contraction has ended)
Technically inadequate strips
Common Errors in Documentation
Failure to recognize non-reassuring or abnormal
uterine activity
Failure to take steps once non-reassuring
characteristics are noted
Failure to communicate changes in patient
condition in the medical record and to the
physician
Failure to continue monitoring until delivery
Monitoring Methods
Auscultation and Palpation
In order to hear fetal heart beats at various stages of development go to
http://heartbeatsathome.com/dopplerdetails.cfm
Auscultation
Advantages
Inexpensive, non-invasive
Assesses rate and significant rate changes of accelerations and decelerations
Disadvantages
DeLee Stethoscope
Doppler ultrasound device
Provides no permanent record for documentation
Does not allow for subtle changes
Requires 1:1 nurse:patient ratio
Interpretation
Performed during a contraction and for 30 seconds thereafter
Palpation
Advantage
Non-invasive
Can detect contraction frequency and duration, however intensity is
subjective
Disadvantage
Provides no permanent record for documentation
Cannot assess relationship between FHR and contractions
Electronic Monitoring
Indirect (external monitoring)
Technique
Advantages
Ultrasound transducer
Tocodynamometer
Non-invasive
Continuous
Provides Record
Disadvantages
Movement or change
of position may
affect tracing
Obesity
Maternal pulse
Greater than 240; less
Than 50
Cant detect dysrhythmias
-2
Direct (internal)
Technique
Advantages
Internal scalp
electrode
Intrauterine
pressure catheter
More direct
Not affected by
movement or
change of position
Measures contraction
intensity
Disadvantages
Membranes must be
ruptured; 1 CM dilation
Infection
Fetal trauma
Additional Information
A test pattern must be run and documented prior to
monitoring (press test button on monitor)
Paper speed at should be set at 3 cm/minute
Uterine baseline reference should be set at 10 mmHg
if monitoring externally and 0 if using an intrauterine
pressure catheter (press UA button on monitor)
Internal monitoring is contraindicated in AIDS,
Herpes, and know Beta Strept infections
Maternal/Fetal Oxygen Transport:
Acid/Base Balance
ACID-BASE BALANCE
Monitoring acid-base balance
Direct
PUBS (percutaneous umbilical blood sampling
Serial scalp sampling
Umbilical cord pH
Fetal pulse oximetry
Indirect
Baseline FHR
Variability
Accelerations
Decelerations
Factors Affecting 02/C02 Transport
(Acid-Base Balance)
Maternal
Placental
Anomalies: Tumors, calcifications`
Abruptions, Previas
Umbilical Cord
Medical conditions such as PIH, diabetes, seizures
Maternal substance abuse
Maternal medication
Anomalies
Compression: True knot; nucal cord, prolapse
Fetal
Anomalies: Anencehphaly, neural tube defects
Infection
ABO incompatibilities; RH sensitization
Normal Placental Function
Normal uterine blood
flow
Umbilcal Vein
Umbilical Arteries
Oxygenation in the
intervillous space
Exchange of O2/C02
Normal Acid/Base Values
Maternal:
-pH
-Pa02
-PaC02
-Bicarb
7.40-7.45
104-108 mm Hg
27-32 mm Hg
16-20 mEq/L
Maternal pulse oximetery should remain at 98-100%
< 94% is trending toward incompatible with fetal life
<90% is incompatible with fetal life
Fetal
-pH
Pa02
PaC02
-BD
7.25-7.35
20-30 mm Hg
40-50 mm Hg
< 10 mEq/L
Umbilical Cord:
Arterial
Umbilical Cord:
-pH
7.34 + 0.03
Pa02
26 +5 mmHg
PaC02 34 +6 mmHg
-pH >7.20
-Pa02>20 mmHg
-PaC02<60 mmHg
Venous
Fetal Scalp Sampling Values
Normal
Borderline
Acidosis
Critical
>7.25 mmHg
7.20-7.25
<7.20
<7.00
Respiratory vs Metabolic Acidosis
Respiratory
Metabolic
-pH
<7.20
-pH
<7.20
-Pa02
-PaC02
-BD
variable
>60 mmHg
<10mEq/L
-Pa02
-PaC02
-BD
<20 mm Hg
44-55 mmHg
> 10 mEq/L
Something New: Intrapartum
Oxygen Saturation Monitoring
Purpose
Measures O2
saturation in utero
Procedure
Insert catheter with
O2 sensing
microchip
Evaluating Baseline Fetal Heart
Rate
Fetal heart tones
contraction
FHR: Baseline
Norms
110-160 beats/minute
Ten minute period which excludes accelerations and
decelerations
Physiology: the Autonomic Nervous System
Sympathetic-dominant system until around the 28 th week of
gestation; cardioaccelerator
Parasympathetic-develops around the 28 th week of gestation;
cardiodecelerator
The interaction between the sympathetic and parasympathetic
produces variability in the fetal heart rate. It is demonstrated
on a strip by a squiggly line and is defined in terms of
absent, minimal, average, or marked variability
Normal Rhythm
Select one minute of strip
in which to evaluate fetal heart rate
Normal Rate Between 110-160 BPM
Each horizontal line
Represents 10 beats
60 sec from
One heavy line to next
120s130s
Select one minute of strip. Determine
highest fetal rate and lowest fetal rate during that minute.
The difference will represent variability. Using above: 130-120=10
Therefore the variability falls in the average range
FHR: Bradycardia
Norms
Causes
Fetal Heart Rate less than 110 x 10 minutes
Maternal/fetal infection
Prolonged maternal hypotension
Postmaturity
Fetal heart block
Interventions
Treat cause; in event of fetal heart block, the condition will often
correct after delivery. Intervention will occur after delivery.
Determine fetal heart rate and variability
FHR: Tachycardia
Norms
Causes
Fetal heart rate above 160 BPM for longer than 10 minutes.
Maternal fever
Maternal hypovolemia
Maternal/fetal infection
Medications such as Brethine
Interventions
Treat the cause
Using the examples for normal rhythm, determine fetal heart rate and variability
On the section of strip between red arrows.
Baseline above 160 BPM x 10 minutes
Determining Fetal Heart Tone
Variability
Amplitude of FHR
Change
Description
Undetectable from baseline Absent
Visually detectable from
baseline 5 beats per
minute
Minimal
6-25 beats per minute
Moderate
> 25 beats per minute
Marked
FHR: Variability
Absent Variability
Obstetrical Emergency!
Reposition Mother
IV fluid bolus of at least 500 ml LR or NS
O2 per mask at 10-12 L
Cease infusions of Pitocin
Notify Physician
Possibly ready for C/S
Absent Variability
FHR: Minimal Variability
Causes:
CNS depression
Volume depletion
Response to Medication
Significance:
O2 suppression to fetus
Intervention:
Fluid replacement
O2
FHR: Increased Variability
Causes
Significance
Immediate response to a hypoxic event
O2 saturation is being compromised
Intervention
Reposition
FHR: Sinusoidal Pattern
Description
Seesaw pattern that is uniform (see next slide)
Significance
Prolonged pattern may indicate an Rh
sensitization
Medications such as Nubain may cause periodic
sinusoidal patterns
Fetal Heart Tone Patterns
FHR: Accelerations
Causes
Response to fetal movement or stimulation
Description
Abrupt increase of fetal heart rate above baseline of 15 beats per
minute (bpm) and lasting 15 seconds bur < 2 minutes from the
onset to return to baseline.
Before 32 weeks of gestation, a peak 10 bpm above the baseline
and duration of 10 seconds is an accelerations.
Interventions
None
Accelerations
Decelerations
Early: This declaration reflects the vagal stimulation of the
compression of the uterus on the fetal head (head compression)
Late: The lowest point of the deceleration usually occurs after
peak of the contraction and does not return to the baseline until
after the contraction is completed. Often it is 15-30 seconds
before the fetal heart rate has returned to the baseline after The
contraction has completed.(utero-placental insufficiency)
Variable: Abrupt decrease of heart rate and rapid recovery.
Usually 15 bpm and last about 15-20 seconds. Associated with
cord compression
Prolonged: A decrease in baseline that may last from 2-20
minutes. Cause is unknown
FHR: Early Decelerations (can only be
evaluated when a contraction is present)
Causes
Description
Head compression
Decrease of heart rate which mirrors a contraction; the
heart rate will begin to decelerate at the onset of a
contraction and will return to baseline as the contraction
eases.
Intervention
None
FHR: Late Decelerations (Can only be evaluated
when a contraction is present)
Causes
Uteroplacental perfusion has be compromised
Description
Fetal heart rate will begin to decelerate around the peak of the contraction and
not return to the baseline until about 15-30 seconds after the contraction has
ended
Any deceleration of the fetal heart tones from the baseline lasting greater than
30 seconds
Intervention
Fetal Stress Protocol:
Position mother on side (either right or left)
O2 per mask at 10-12 L/min
IV fluid bolus of 350-500 cc fluid (preferably LR or D5LR)
Discontinue pitocin
Late Deceleration-Returning to baseline about 30 seconds after contraction has ended
Where is the baseline? Often it is difficult
to assess. In this case the decels are late.
FHR: Variable Decelerations (May occur
with or without a contraction)
Causes
Cord compression
Description
Deceleration will occur very quickly and return to
baseline as quickly. This gives the deceleration a V
shape. As they prolong, the shape changes to a U
Intervention
Reposition mother from side to side. In prolonged cases,
O2 and IV fluid may be given using the Fetal Stress
Protocol.
FHR: Prolonged Decelerations
Causes
Description
Unknown; may occur during a prolonged contraction; it is
often noted at the time the cervix is completely dilated
Prolonged decrease in fetal heart rate; may last as long as
5-10 minutes before returning to baseline
Interventions
Reposition mother; ensure adequate hydration and
oxygenation
-2
Non-reassuring
Progressive increase or decrease in
baseline
Tachycardia
Progressive decrease in baseline
variability
Severe variable decelerations
-2
Non-reassuring
Late decelerations
Absence of variability
Prolonged decelerations
Severe bradycardia
Caring for the Mom,
Not the Monitor!
