CTG

Aboubakr Elnashar

Benha University Hospital, Egypt

Aboubakr Elnashar

Antepartum

CTG

Aboubakr Elnashar

Fetal heart rate recording

1.CTG

2.NST

3.Contraction stress test

4.Nipple stimulation test

5.Acoustic stimulation test

6.Computerized CTG

Aboubakr Elnashar

1. The Non-Stress Test (NST) (Hammacher et al, 1960)

Idea: • FHR accelerations:

linked closely with fetal movements

{increased sympathetic output}.

• The long term variability:

{balance between sympathetic & parasympathetic

tone}

• The short term variability (baseline or bandwidth

variability)

{parasympathetic tone}.

Aboubakr Elnashar

Steps:

1. left lateral recumbent position.

2. Place and adjust the external tocodynamometer

and ultrasound transducer to obtain the best

possible tracing.

3. Instruct the patient to record fetal movements on

the monitor tracing using the event marker.

4. Observe the EFM tracing until the criteria for a

reactive test are met

(minimum of 20 mins and maximum of 60 mins).

Aboubakr Elnashar

In the event of lack of fetal movement, apply

stimulation e.g. fetal acoustic stimulator.

Record any relevant clinical information on the

EFM tracing e.g.

blood pressure, temperature, maternal heart rate,

loss of contact

changes in maternal position.

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Interpretation: Reactive:

2 accelerations of FHR in 20 min.

Each acceleration 15 beat & lasts 15 secs.

Non-reactive:

no accelerations in 40 min.

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•Reactive:

increase of FHR to >15 beats/min for > 15 sec

following fetal movements

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•Nonreactive nonstress test followed by contraction

stress test showing mild late decelerations.

•CS was performed and the severely acidemic fetus

could not be resuscitated.

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Positive CST= late deceleration in 50% of UC.

Non reactive NST= No HR acceleration

Cessation of fetal movement

Basal line tachycardia > 160 bpm

Basal line bradycardia <110 bpm

Sequence of events with placental insufficiency

or hypoxia

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2. Fetal heart rate tracings (CTG) 1.Normal/Reassuring

Baseline

HR: 110-150 b/m

Variability: 10-25 b/m

At least 2 accelerations

(>15 beats for> 15 seconds in 20 min)

No decelerations.

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2. Suspicious/Equivocal Trace.

Baseline

HR: 150-170 b/m or 100-110 b/m

Variability: Reduced (5-10 b/m for >40 m)

Absence of accelerations for >40 m

Sporadic deceleration of any type.

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3. Abnormal/Pathological

Baseline

HR: <100 b/m or > 170 b/m

Variability:

No area of normal baseline variability

Silent Pattern (<5 b/m) for >40 min

Sinusoidal pattern (oscillation frequency= 2-5

cycles/min, amplitude of 5-15 b/m) for >40 m

No accelerations

Repeated late, prolonged (> 1 minute) and

severe variable (>40 b/m) decelerations.

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A:

Absence of

accelerations,

diminished

variability,

late decelerations

with weak

spontaneous

contractions.

B:

Normal

accelerations

Normal variability

15 beat

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CTG: Tachycardia

Sinusoidal pattern

Late deceleration Aboubakr Elnashar

Intrapartum

CTG

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Basal Heart Rate Activity • Rate: Normal:110-160 increment 5 bpm (10 m segment) Bradycardia: < 110 bpm Tachycardia: > 160bpm • Variability :Short term= instantaneous (beat to beat v.) :Long term= oscillatory changes in 1 m • Sinusoidal: :Mild is due to sedation :Marked is due to fetal anemia Arrhythmia: Abrupt spiking, bradycardia or tachy

Periodic heart rate Activity • Acceleration • Deceleration

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Baseline The mean FHR rounded to increments of 5 bpm

during a 10-min segment, excluding:

— Periodic or episodic changes

— Periods of marked FHR variability

— Segments of baseline that differ > 25 bpm

Tachycardia

Baseline FHR > 160 bpm

Bradycardia

Baseline FHR < 110 bpm

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•Fetal

bradycardia

measured

with a scalp

electrode in a

pregnancy

complicated

by placental

abruption

and

subsequent

fetal death.

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Placental abruption.

In the upper panel, the fetal scalp electrode first detected the

heart rate of the dying fetus. After fetal death, the maternal

electrocardiogram complex is detected and recorded.

The second panel displays an absence of uterine

contractions.

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Variability

Reduced variability is the single most reliable sign of fetal compromise

The baseline must be for a minimum of 2 min in

any 10-min segment

Fluctuations in the FHR of two cycles per min or

greater

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Variability is visually quantified as the amplitude of

peak-to-trough in bpm

Absent: amplitude range undetectable

Minimal: amplitude range detectable but 5 bpm

Moderate (normal): amplitude range 6–25 bpm

Marked: amplitude range > 25 bpm

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Short-term beat-to-beat variability

measured by a fetal scalp electrode

(t= time interval between successive fetal R

waves). Aboubakr Elnashar

long-term beat-to-beat variability

ranging between 125 and 135 bpm).

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(1) Undetectable or absent

(2) Minimal variability:0 -5 bpm Aboubakr Elnashar

4) Marked variability : >25 bpm

(3)Moderate variability : >5-<25 bpm

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External fetal heart

recording:

A. lack of long-term

variability at 31 w

during maternal

diabetic ketoacidosis

(pH 6.09).

B. Recovery of fetal

long- term variability

after correction of

maternal acidemia.

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Sinusoidal Heart Rate

• Flat short term variability

• Ampllitude: 5-15bpm

• 2- 5 cycle/m

• Absence of accelerations

Mild: due to sedation

Marked: due to fetal anemia

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•Sinusoidal fetal heart rate pattern associated with maternal

intravenous meperidine administration.

•Sine waves are occurring at arate of 6 cycles/min.

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•Arrhythmia: •Abrupt spiking

Internal fetal monitoring:

•occasional abrupt beat-

to-beat fetal heart rate

spiking due to erratic

exrasystoles shown in

the superimposed fetal

electrocardiogram.

•The normal infant was

delivered

spontaneously and had

a normal cardiac rhythm

in the nursery.

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Periodic heart rate Activity

Acceleration

Deceleration

Aboubakr Elnashar

Acceleration A visually apparent increase (onset to peak in less

than 30 sec) in the FHR from the most recently

calculated baseline

The duration= time from the initial change in FHR

from the baseline to the return of the FHR to the

baseline

Aboubakr Elnashar

At 32 w and beyond

an acceleration has an acme of 15 bpm above

baseline, with a duration of 15 sec but < 2 min

Before 32 w

an acceleration has an acme 10 bpm above

baseline, with a duration of 10 sec but < 2 min

Prolonged acceleration lasts 2 min, but < 10 min

If an acceleration lasts 10 min, it is baseline

change

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Deceleration 1. Early deceleration In association with a uterine contraction, a

visually apparent, usually symmetrical, gradual—

onset to nadir 30 sec—decrease in FHR with

return to baseline

Nadir of the deceleration occurs at the same

time as the peak of the contraction

Aboubakr Elnashar

Early

deceleration:

Gradual decrease

in the heart rate with

both onset and

recovery coincident

with the onset and

recovery of the

contraction.

Nadir of the

deceleration is

30seconds or more

after the onset of the

deceleration.

Aboubakr Elnashar

2. Late deceleration In association with a uterine contraction, a visually

apparent, gradual—onset to nadir 30 sec decrease

in FHR with return to baseline

Onset, nadir, and recovery of the deceleration

occur after the beginning, peak, and end of the

contraction, respectively

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•Late deceleration. Gradual decrease in the heart rate

Nadir and recovery occurring after the end of the contraction.

Nadir of deceleration occurs 30 seconds or more after the onset of the

deceleration. Aboubakr Elnashar

•Late

decelerations

{uteroplacental

insufficiency

resulting from

placental

abruption}.

ImmediateCS

•Umbilical artery

pH was 7.05 and

the Po2 was 11

mm Hg.

Aboubakr Elnashar

3. Variable deceleration An abrupt onset to nadir < 30 sec, visually

apparent decrease in the FHR below the baseline

The decrease in FHR is 15 bpm, with a duration of

15 sec but < 2 min

Complicated variable decelerations

depth >60 bpm for >60 seconds

changes in shape: over-shoot, decreased or

increased baseline FHR following the

decelerations,or

absence of baseline variability in or between

decelerations,

slow recovery

Aboubakr Elnashar

Variable decelerations.

abrupt decrease in the

heart rate with onset

commonly varying with

successive contractions.

decelerations measure ≥

15 bpm for 15 seconds or

longer

Onset to nadir phase of

less than 30 seconds.

Total duration is less

than 2 minutes.

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•Variable

decelerations

B “shoulders” of

acceleration

compared with

deceleration A.

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FHR effects of partial

occlusion and

complete occlusion of

the umbilical cord

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4. Prolonged deceleration Visually apparent decrease in the FHR below the

baseline

Deceleration is 15 bpm, lasting 2 min but < 10 min

from onset to return to baseline

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Abrupt decrease

>15 bpm

Often drops<100

>2 m & < 10 m

Variable pattern

•Prolonged

deceleration

{uterine hyperactivity}

Approximately 3

minutes are shown but

FHR returned to

normal after uterine

hypertonus resolved.

Vaginal delivery later

ensued.

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Fetal heart rate

effects of

manual

compression of

a prolapsed

umbilical cord in

a 25-week

footling breech.

A shows the

effects of 25-

second

compression

compared with

40 seconds in

B. Aboubakr Elnashar

Early Deceleration Late Deceleration

Variable Deceleration

Abrupt decrease

>15 bpm

Often drops<100

>15 S& < 2 m

Variable pattern

Abrupt decrease

>15 bpm

Often drops<100

>2 m & < 10 m

Variable pattern

Prolonged Deceleration

may drops<100 Usually did not drops<100

Decelerations

Aboubakr Elnashar

Indications for continuous EFM 1. High-risk pregnancies where there is an

increased risk of perinatal death, cerebral palsy or

neonatal encephalopathy.•B

2. Where oxytocin is being used for induction or

augmentation of labour.•C

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INTERPRETATION

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a)Normal/Reassuring Trace

- At least two accelerations (> 15 beats per minute

for >15 seconds) in 20 minutes

- Baseline heart rate: 110-150 bpm

- Baseline variability: 5-25 bpm

- Early decelerations (in late first stage of labour)

Aboubakr Elnashar

b)Suspicious/Equivocal Trace

- Absence of accelerations for >40 minutes

(non reactive)

- Baseline heart rate: 150-170 bpm or 100-110 bpm

(normal variability, no decelerations)

- Silent pattern (<5 bpm for >40 minutes) although

normal baseline (110-150 bpm), no

decelerations

- Baseline variability >25 bpm in the absence of

accelerations

- Variable decelerations (depth <60 bpm, duration

<60 seconds)

- Occasional transient prolonged bradycardia if

FHR drops to <80 bpm for >2 minutes or

<100 bpm For >3 minutes Aboubakr Elnashar

b)Abnormal/Pathological Trace - Baseline FHA> 150 bpm + silent pattern and/or repeated late or

variable decelerations

- Silent pattern for >90 minutes

- Complicated variable decelerations (depth >60 bpm for >60

seconds, changes in shape: over-shoot, decreased or

increased baseline FHR following the decelerations, or absence

of baseline variability in or between decelerations, slow

recovery)

- Combined/biphasic decelerations (variable followed by late)

- Prolonged bradycardia in a suspicious trace

- Prolonged bradycardia> 10 minutes with no signs of recovery

- Repeated late decelerations

- Pronounced loss of baseline variability regardless of baseline

FHR with shallow late decelerations

- Sinusoidal pattern with no accelerations

Aboubakr Elnashar

Aboubakr Elnashar

MANAGEMENT a)Normal/Reassuring

risk of fetal hypoxia in spontaneous labour is low.

Manage normally.

b)Suspicious/Equivocal

continue EFM

amniotomy should be performed

+/- fetal scalp blood pH if meconium stained

liquor is present.

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Initial Evaluation and Treatment of Nonreassuring

Fetal Heart Rate Patterns

Discontinuation of any labor stimulating agent

Cervical examination:

umbilical cord prolapse or

rapid cervical dilation or

descent of the fetal head

Changing maternal position to left or right lateral

recumbent position, reducing compression of the

vena cava and improving uteroplacental blood flow

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Monitoring maternal blood pressure level for

evidence of hypotension, especially in those with

regional anesthesia—if present, treatment with

ephedrine or phenylephrine may be warranted

Assessment of patient for uterine hyperstimulation

by evaluating uterine contraction frequency and

duration

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During episodes of abnormal FHR patterns when

the mother is lying supine, the mother should adopt

the left-lateral position.•B

In the presence of abnormal FHR patterns and

uterine hypercontractility not secondary to oxytocin

infusion, tocolysis should be considered. A

suggested regime is subcutaneous terbutaline

0.25 milligrams.•A

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c)Abnormal/Pathological

Amniotomy

Fetal scalp blood pH if meconium stained liquor

to determine subsequent management or

Deliver if clinically indicated.

Deliver if fetal scalp pH required but not

obtainable i.e. if cervix not sufficiently dilated or

equipment not available.

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In cases of suspected or confirmed acute fetal

compromise, delivery should be accomplished as

soon as possible, accounting for the severity of the

FHR abnormality and relevant maternal factors.

The accepted standard has been that ideally this

should be accomplished within 30 minutes. •B

Aboubakr Elnashar

Fetal blood sampling

should be undertaken with the mother in the left-lateral

position.•B

Contraindications to fetal blood sampling :•B

Maternal infection (e.g. HIV, hepatitis viruses and

herpes simplex virus)

Fetal bleeding disorders (e.g. haemophilia)

Prematurity (< 34 weeks).

Where there is clear evidence of acute fetal

compromise (e.g. prolonged deceleration greater than

three minutes), fetal blood sampling should not be

undertaken and the baby should be delivered urgently.•.

Aboubakr Elnashar

All scalp pH estimations should be interpreted taking into account

the previous pH measurement,

the rate of progress in labour and the

clinical features of the mother and baby.

Aboubakr Elnashar

Maternal facial oxygen therapy

Prolonged use of maternal facial oxygen therapy

may be harmful to the fetus and should be

avoided.

There is no research evidence evaluating the

benefits or risks associated with the short-term use

of maternal facial oxygen therapy in cases of

suspected fetal compromise .•C

Aboubakr Elnashar

Thank you

Aboubakr Elnashar