fetal monitoring during labour

1. Cardiotocography
1
Presented By
Nirsuba Gurung
MN,Women Health and
Development
4/24/2016

2. 4/24/2016 2

3. Cardiocotography
• Cardiotocography (CTG) is a
continuous electronic record of the
fetal’s heart rate obtained via an
ultrasound transducer placed on the
mother’s abdomen
• It is sometimes referred to as
‘electronic fetal monitoring’ (EFM)
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4. CTG Contd…..
• The machine used to perform the
monitoring is called a
cardiotocograph, more commonly
known as an electronic fetal monitor
(EFM)
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5. Invention
• The invasive fetal monitoring was
invented by Doctors Alan
Bradfield, Orvan Hess and
Edward Hon.
• A refined (antepartal, non-
invasive, beat-to-beat) version
(cardiotocograph) was later
developed for Hewlett Packard by
Dr. Konrad Hammacher.
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8. Purpose
• To record FHS continuously
• To check uterine activity
• To detect any fetal distress
• To gain information about rate,
rhythm of the fetal heart rate and
fetal movement

9. Indications
for the
use of
continuous
EFM
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10. Indication
Continuous EFM should be offered and
recommended for high-risk
pregnancies where there is an increased risk
of perinatal death,
cerebral palsy or neonatal encephalopathy.
Continuous EFM should be used where
oxytocin is being used for
induction or augmentation of labour.
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11. ADMISSION CTG
Current evidence does not
support the use of the
admission CTG in low-risk
pregnancy and it is therefore
not recommended
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12. High-Risk Indications
Maternal medical illness
Gestational diabetes
Hypertension
Asthma
Obstetric complications
Multiple gestation
Post-date gestation
Previous cesarean section
Intrauterine growth restriction
Oligohydramnios
Premature rupture of the membranes
Congenital malformations
Third-trimester bleeding
Oxytocin induction/augmentation of labor
Preeclampsia
Meconium stained liquor
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13. A Continuous EFM should be
offered and recommended in
pregnancies previously monitored
with intermittent auscultation:
• if there is evidence on
auscultation of a baseline less than
110 bpm or greater 160 bpm
• if there is evidence on auscultation
of any decelerations
• if any intrapartum risk factors
develop.
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14. Methods
External Cardiotocography-
For continuous or intermittent monitoring
of
• The fetal heart rate and
• The activity of the uterine muscle
• Placed two transducers on the mother's
abdomen(one above the fetal heart and
the other at the fundus).

15. External(Indirect) Monitoring
The
tocodynamometer
(“toco”) is placed
over the uterine
fundus. The toco
provides
information that
can be used to
monitor uterine
contractions.
The
ultrasound
device is
placed over
the area of
the fetal
back. This
device
transmits
information
about the
FHR.

16. The pressure transducer
transmits the pressure
generated
by uterine contractions
in mm Hg.
•Each small vertical
square is 5 mm Hg
•Each small horizontal
square is 10 seconds .
•Each large horizontal
square is 1 minute .
Pressure
Transducer
Toco sensor

17. Ultrasound transducer
The ultrasound probe
transmits the
fetal heart rate in
beats per minute.
•Each small vertical
square is 10 beats.
•Each small horizontal
square is 10 seconds .
•Each large horizontal
square is 1 minute .4/24/2016 17
Ultrasound Probe

18. • Information from both the toco and
the ultrasound device is transmitted
to the electronic fetal monitor.
• The FHR is displayed in a digital
display (as a blinking light), on the
special monitor paper, and audibly
(by adjusting a button on the
monitor). The uterine contractions
are displayed on the special monitor
paper as well. 18

19. Internal Cardiotocography-
• Uses an electronic transducer connected
directly to the fetal scalp through the
cervical opening and is connected to the
monitor.
• Internal monitoring provides a more
accurate.
• Internal monitoring may be used when
external monitoring of the fetal heart rate
is inadequate.
• It need some degree of cervical dilatation.

20. Internal Monitoring
Criteria for Internal Monitoring:
 Amniotic membranes must be
ruptured
 Cervix dilated 2 cm.
Presentation must be cephalic
 Presenting part down against the
cervix

21. • Spiral Electrode is placed on the
fetal occiput which allows for more
accurate continuous data than
external monitoring.
• Also is not affected by mom or fetal
movement as with external
monitoring.
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22. Internal Monitoring
The spiral electrode is
attached to the
fetal scalp
Wires that extend
from attached spiral
electrode are attached
to a leg plate and then
attached to electronic
fetal monitor.

23. Procedure
Equipments
• Cardiotocograph
• Transducer(2):Toco and cardio
• Conduction gel or paste
• Abdominal binder (two belts)
• Monitor paper
• Tissue paper
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25. Preparation for CTG
• Determine the indication for fetal
monitoring
• Explain the purpose, time required for
test
• Instruct the women for empty the
bladder
• Place the women in supine position
• Uncover the abdomen

26. Procedure
• Place the tocosensor on the fundus of utreus
and fix it with abdominal binder
• Identify the presentation and position of the
fetus
• Localize the FHS and fix it with abdominal
binder

27. Procedure
• Assure the recording of FHS and
uterine contraction
• Explain the mother to push the
bottom when she feel any
movements
• Labeled the women’s name, I.P.
number, date and time in CATAG
graph
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28. Procedure
• Turn off the monitor and replace
• Read the CTG and immediately notify
the doctor ,if any abnormality seen
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29. Interpretation
• Uterine activity (contractions)
• Baseline fetal heart rate (FHR)
• Baseline FHR variability
• Presence of accelerations
• Periodic or episodic decelerations
• Changes or trends of FHR patterns over time.

30. Uterine activity
(contraction)
• Frequency- the amount of time between the
start of one contraction to the start of the
next contraction.
• Duration :The amount of time from the start
of a contraction to the end of the same
contraction
• Intensity (strongeness):a measure of how
strong a contraction is. In early labour the
contractions are weak, with amplitude of about
20 mm Hg and at the end of the first stage 60
mm Hg

31. Uterine activity
(contraction)
• Resting Tone- a measure of how relaxed the
uterus is between contraction(between 4-10
mm Hg)
• Interval- the amount of time between the end
of one contraction to the beginning of the
next contraction.

32. • Record the number of contractions
present in a 10 minute period - e.g. 3 in
10
• Each big square is equal to 1 minute, so
look how many contractions occurred in
10 squares
• Individual contractions are seen as peaks
on the part of the CTG monitoring
uterine activity
• assess contractions for duration and

33. Baseline fetal heart rate
The mean level of the FHR when
this is stable, excluding
accelerations and decelerations. It
is determined over a time period of
5 or 10 minutes and expressed in
bpm.
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34. – Normal Baseline FHR 110–160 bpm
– Moderate bradycardia 100–109 bpm
– Moderate tachycardia 161–180 bpm
– Abnormal bradycardia < 100 bpm
– Abnormal tachycardia > 180 bpm
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36. Baseline Fetal Heart rate
Normal Pattern
• Baseline FHR = 110 – 160 bpm

37. Baseline variability
•Variability refers to the normal
beat to beat changes in FHR.
• Normal variability is between 5-
15 bpm.
•Variability can be measured by
analysing a one-minute portion of
the CTG by estimating the
difference in beats per minute
between the highest peak and
lowest trough of fluctuation in a
one-minute segment of the trace
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38. Baseline variability
The fluctuations are visually quantities as
the amplitude of the peak-to-trough in
bpm. Using this definition, the baseline
FHR variability is categorized by the
quantitated amplitude as:
• Absent- undetectable
• Minimal- greater than undetectable, but
less than or equal to 5 bpm
• Moderate- 6-25 bpm
• Marked- greater than 25 bpm
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43. FHR Variability
Absent variability =
Amplitude range
undetectable
Minimal = < 5 BPM
Moderate = 6 to 25 BPM
Marked = > 25 BPM

44. Accelerations
• To be called an acceleration, the peak must
be greater than or equal to 15 bpm, and the
acceleration must last greater than or equal
to 15 seconds from the onset to return to
baseline.
• Prolonged acceleration: is greater than or
equal to 2 minutes but less than 10 minutes in
duration.
• Before 32 weeks of gestation, accelerations
are defined as having a peak greater than or
equal to 10 bpm and a duration of greater
than or equal to 10 seconds.

45. ACCELERATIONS
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47. Deceleration
Decreases in fetal heart rate from the
base line by at least 15b/m, lasting for
at least 15 seconds.

48. DECCELERATIONS
• EARLY : Head compression
• LATE : U-P Insufficiency
• VARIABLE : Cord compression
Primary CNS dysfn
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49. Early Deceleration
• Early Deceleration: Early begin at start
of uterine contraction and end with
conclusion of contraction. Early
decelerations are not a sign of fetal
problems.
• In most cases the onset, nadir(lowest
point), and recovery of the deceleration
are coincident with the beginning, peak,
and ending of the contraction, respectively

50. EARLY
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51. Early Decelerations
• Related to Head Compression
• Intervention
– No intervention necessary. Just continue to
watch for any changes.

52. Early decelerations contd…
• Early decelerations are a benign(
kind/ gentle) finding caused by a
vasovagal response as a result of
fetal head compression by the
contraction.
• Pressure on the fetal skull alters
the cerebral blood flow and this
in turn stimulates the vagus
nerve

53. Early Decelerations

56. Variable Deceleration

57. Variable Deceleration
• Variable decelerations are variable in
duration, intensity, and timing

58. Variable decelerations
Abrupt(sudden) decrease in FHR of > 15 beats
per minute measured from the most recently
determined baseline rate.
The onset of deceleration to nadir is less
than 30 seconds.
The deceleration lasts > 15 seconds and less
than 2 minutes.

59. VARIABLE
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60. Variable Decelerations
• Related to cord compression
• Intervention
– Reposition
– Amnioinfusion

62. variable deceleration contd…
• The umbilical vein is often occluded first
causing an acceleration in response
• Then the umbilical artery is occluded
causing a subsequent rapid deceleration
• When pressure on the cord is reduced
another acceleration occurs & then the
baseline rate returns
• Accelerations before & after a variable
deceleration are known as the “shoulders
of deceleration”
• There presence indicates the foetus is not
yet hypoxic & is adapting to the reduced
blood flow.

64. Late Deceleration

65. Late Deceleration
Gradual decrease in FHR with onset of
deceleration to nadir >30 seconds.
Onset of the decleration occurs after the
beginning of the contraction, and the
nadir of the deceleration occurs after
the peak of the contraction.

66. Late Decelerations
• Related to decreased uteroplacental
perfusion

68. LATE
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70. Late Deceleration
• The fetal heart tones return to the
baseline AFTER end of contraction

71. Two varieties of late decelerations reflex
and nonreflex.
• Reflex late decelerations: are those
which occur in the presence of normal
FHR variability
• Non-reflex late decelerations occur in
association with diminished or absent
FHR variability.

72. • Reflex late decelerations are thought to
be due to vagal stimulation by
chemoreceptors in the head in response
to low oxygen tension.
• The hypoxemia -----increased
sympathetic stimulation ------- increased
systemic vascular resistance. The
response to this increased pressure is a
vagally mediated decrease in heart rate.
• This dual reflexive response may explain
the delay in the heart rate following a
contraction.
• Reflex late decelerations are associated
with normal FHR variability because CNS
system is intact.

73. • Nonreflex late decelerations are
associated with a greater degree of
relative hypoxemia and result in
hypoxic depression of the
myocardium coupled with the
previously described vagal response.
• In reflex late decelerations,
variability was maintained because
the fetus was able to compensate,
shifting oxygenated blood to vital
organs (e.g., the heart),

74. • But in nonreflex late decelerations,
the fetus is unable to compensate. It
is these late decelerations which are
more typically associated with fetal
acidosis, and they are more commonly
associated with placental dysfunction
rather than uterine hypoperfusion or
hyperactivity.
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75. Late Decelerations
Management
• Place patient on side
•Administer O2 by tight face mask
•Discontinue oxytocin.
•Correct any hypotension
•IV hydration.
•If hyperstimulation is present consider terbutaline
0.25 mg SC
•If late decelerations persist for more than 30 minutes
despite the above maneuvers, fetal scalp pH is
indicated.
•Scalp pH > 7.25 is reassuring, pH 7.2-7.25 may
be repeated in 30 minutes.
•Deliver for pH < 7.2 or minimal baseline
variability with late or prolonged decelerations
and inability to obtain fetal scalp pH
These maneuvers are primarily intended to alleviate "reflex" lates.

76. Prolonged Deceleration
A prolonged deceleration is present when there is a
visually apparent decrease in FHR from the baseline
that is greater than or equal to 15 bpm, lasting
greater than or equal to 2 minutes, but less than 10
minutes.
• If it lasts between 2-3 minutes it is classed as Non-
Reasurring
• If it lasts longer than 3 minutes it is immediately
classed as Abnormal
• Action must be taken quickly – e.g. Foetal blood
sampling / emergency C-section

77. Prolonged Deceleration:
A deceleration that lasts greater than or
equal to 10 minutes is a baseline change.

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81. Categorisation of fetal heart rate traces
Category Definition
Normal All four reassuring
Suspicious 1 non-reassuring
Rest reassuring
Pathological 2 or more non-
reassuring
1 or more abnormal
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82. SPECIAL
PATTERNS
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83. Sinusoidal pattern
A regular oscillation of the baseline long-term
variability resembling a sine wave. This smooth,
undulating pattern, lasting at least 10 minutes, has a
relatively fixed period of 3–5 cycles per minute and an
amplitude of 5–15 bpm above and below the baseline.
Baseline variability is absent
Associated with -
Severe chronic fetal anaemia
Severe hypoxia & acidosis
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84. SINUSOIDAL
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85. PSEUDOSINUSOIDAL
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86. SOME
INTERESTING
CASES
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87. ACCELERATION OR DECCELERATION ???
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88. BASELINE BRADYCARDIA WITH
ACCELERATIONS
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89. HALVING PHENOMENON
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90. EXCESSIVE VARIABILITY???
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91. GESTATIONAL DM ; NST ; 8:30am
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92. GDM ; CST ; 12 noon
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93. 4/24/2016 93

94. References
• Dutta, D.C. (2004).Text book of
Obstetrics. Sixth edition, New Central
book agency
• Arias, F. Daftary, S.N. & Bhide, A.
G.(2013). Practical guide to high risk
pregnancy and delivery. Third edition,
Elsiever
•
4/24/2016 94Nirsuba Gurung MN
1st year

95. • The Royal Australian and New
Zealand College of Obstetricians and
Gynaecologists (2006) Intrapartum
Fetal Surveillance Clinical Guidelines.
• Baker L, Beaves M, Trickey D and
Wallace E. 2009. Fetal Surveillance:
A Practical Guide. Southern Health
and RANZCOG
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96. Thank you
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