ctg o&g

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Ali SungkarSub Bagian Fetomaternal

Bagian Obstetri dan Ginekologi FKUI/RSUPN - CM

Cardiotocography ( CTG )Electronic Fetal Monitoring

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Fetal Monitoring

• Track the baby’s heart rate during labor.

• Safe procedure that has saved the lives of many babies in high-risk situations.

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Electronic Monitoring

• Indirect (External monitoring)

•Direct (Internal monitoring)

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EFM-ISSUES

Detect fetal hypoxia i.e reduce and avoid harm to the fetus and improve fetal and baby out-come.

Severe acidosis may result in FHR changes.

Could occur in Normal physiological response in labor.

Misunderstanding the physiological and pathphysiological CTGs will improve the Mx ( management).

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EFM Problems and Realities

Electronic Intra-partum FHR Monitoring is now considered mandatory for high-risk pregnancies.

Difficulties with interpretation include over confidence and not-only difference in opinion between practitioners but, also when the same practitioner examines the same CTG twice.

Increases CS rates 1.41%rr. Increases operative vaginal delivery 1.20%rr. And no change in incidence of C Palsy. Reduction in Neonatal seizures rates 0.51% No difference in APGAR scores. ? About the efficacy.

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EFM- Facts

Reliability of interpretation-50-75% are false positive .

False positive Dx reduces to 105 with FBS.

FBS 93% sensitivity, 6% false positive.

PH Vs Lactate -39% Vs 2.3(rr 16.7).

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Electronic Fetal Monitoring-Indications

• Oligohydramnios

• Hypertension.

• Abnormal FHR detected.

• Malpresentation and in labour.

• DM,Multiple Gestation.

• Previous CS.

• Abdominal Trauma.

• Prolonged ROM.

• Meconium Liq.

• High risk pregnancies

• IOL and Augmentation of Labour.

• Reduced FM.

• Premature labour/TPL.

• APH/IPH

Indications for the continuous EFM

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EFM- Interpretation

Consider :

• Intrapartum / antepartum trace.

• Stage of labour.

• Gestation.

• Fetal presentation, ? Malpresentation.

• Any augmentation,? Induction labor Medications ?

• Direct or indirect monitoring

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EFM- 4 Basic Features of FH Trace

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EFM- 4 Basic Features.

• Baseline FHR - Mean level of FHR when this is stable, excluding Accelerations and Decelerations (110-160 bpm)

-Tachycardia

-Bradycardia Baseline Variability-5 bpm or greater than or

equal to 5bpm, between contractions

-Normal

-Non-reassuring-Less than 5 bpm or less but less than 30 min

-Abnormal-less than 5 bpm for 90 min or more.

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Uterine Contraction

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Baseline variability CTGBaseline variability

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FHR: Variability

• Definitions– Short term– Long term

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Baseline variability

• The minor fluctuations on baseline FHR at

3-5 cycles p/m produces Baseline

variability.

• Examine imin segment and estimate

highest peak and lowest trough.

• Normal is more than or equal to 5 bpm.

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Factors affecting Baseline variability.

• Para-Sympathetic affects short term

variability whilst Long Term is more Symp.

• CNS ,Drugs reduce Variability

• High gestation increases variability

• Mild Hypoxia may cause both S and para S

stimulation.

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Non-reassuring Baseline variability.

• NR CTGs- reduced or less than 5 bpm for 40

min or more but less than 90 mins..

• B-B or short Term V is varying intervals

between successive heart beats .

• Long Term v is irregular waves on the CTG

3-5 bpm.

• Normal is 5-25 bpm– this indicates N-CNS.

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EFM-Accelerations

• Accelerations- transient increase in FHR of

15 bpm or more lasting for 15 sec.

• Absence of accelerations on an otherwise

normal CTG remains un clear.

• Presence of FHR Accelerations have Good

outcome.

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EFM Decelerations

• Decelerations-

transient slowing of

FHR below the

baseline level of

more than 15 bpm

and lasting for 15 sec.

Or more.

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Electronic Fetal Monitoring

• a) Early Decelerations

Head compression

Begins on the onset of contraction and

returns to baseline as the contraction

ends.

Should not be disregarded if they

appear early in labor or Antenatal.

Clinical situation should be r/v

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Early Decelerations

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Late Decelerations.

• Uniform periodic slowing of FHR with the on

set of the contractions .

• Repetitive late decels increases risk of

Umbilical artery acidosis and Apgar score of

less than 7 at 5 mins and Increased risk of

CP.

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b) Late Decelerations • Due to acute and chronic feto-placental

vascular insufficiency Occurs after the peak and past the length of

uterine contraction, often with slow return to the baseline.

Are precipitated by hypoxemia Associated with respiratory and metabolic

acidosis Common in patients with PIH, DM, IUGR or

other form of placental insufficiency.

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Late Decelerations

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Late Decelerations

• Reduces Baseline variability together

with Late Decelerations or Variable

Decelerations is associated with

increased risk of CP.

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EFM- Variable Decelerations• Variable intermittent periodic slowing of FHR with

rapid onset recovery and isolation.• They can resemble other types of deceleration in

timing and shape.• Atypical VD are associated with an increased risk

of umbilical artery acidosis and Apgar score less than 7 at 5 min

• Additional components:• Loss of 1 degree or 2 degree rise in baseline Rate• Slow return to baseline FHR after and end of

contraction.• Prolonged secondary rise in Base FHR • Biphasic deceleration• Loss of variability during deceleration • Continuation of base line at a lower level.

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c) Variable Deceleration (Vagal activity)• Inconsistent in configuration, • No uniform temporal r-ship to the onset of

contraction, are variable and occur in isolation.• Worrisome when Rule of 60 is exceeded (i.e.

decrease of 60 bpm,or rate of 60 bpm and longer than 60 sec)

• Caused by cord compression of the umbilical cord• Often associated with Oligo-hydroaminos with or

without ROM• Can cause short lived RDS if they MILD• Acidosis if prolonged and Recurrent.

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Variable Decelerations

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References

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EFM Prolonged deceleration

Prolonged Deceleration

• Drop in FHR of 30 bpm or More lasting for at least 2 min

• Is pathological when crosses 2 contractions i.e 3 mins.

• Reduction in O2 transfer to placenta.

• Associated with poor neonatal outcome.

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EFM- Prolonged DecelerationsCAUSES

• Cord prolapse.

• Maternal hypertension

• Uterine Hypertonia

• Followed by a Vag Exam or ARM or SROM

with High PP.

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Prolonged Deceleration

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EFM Mx Prolonged Deceleration

• Maternal position

• IV fluids

• V.E to exclude cord prolapse

• Assess BP

• FBS if cx dilated and well applied PP

• Mx Depending on the clinical situation.

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Baseline Bradycardia

• FH below 110bpm(FIGO ).

• less than 100bpm (RANZCOG).

Causes.

Postdates, Drugs, Idiopathic,

Arrythmias, hypothermia(increased Vagal Tone)

Cord Compression (Acute Hypoxia, congenital H disease and Drugs).

Mx depends on the clinical situation.(FBS,Vag Exam, Observation or expedite delivery)

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Types

• Moderate Bradycardia 100-109 bpm

• Abnormal bradycardia less than 100bpm.

• Tachycardia 161-180 bpm

• Abnormal Tachycardia more than 180

bpm

• Ranzcog Australian more than 170 bpm

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Baseline tachycardia and Bradycardia.

• Uncomplicated baseline tachycardia

161-180 bpm or bradycardia 101-109

do not appear to be associated with

poor NN outcome.

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Causes of B Tachycardia.

• Asphyxia

• Drugs

• Prematurity

• Maternal Fever

• Maternal thyrotoxicosis

• Maternal Anxiety

• Idiopathy

• Mx depends on the clinical situation

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Electronic Fetal MonitoringBaseline Bradycardia

FH Rate below 110bpm (FIGO Recommended)

Postdates

Drugs

Idiopathic

Arrhythmia's

Hypothermia.(Increased Vagal tone),

Cord compression(Acute Hypoxia,Congenital H/disease, and drugs)

Mx depends on the clinical situation. (FBS, Vag Exam , Observation or expedite Delivery).

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Baseline Tachycardia Asphyxia Drugs Prematurity Maternal fever Maternal thyrotoxicosis Maternal Anxiety Idiopathy

Mx depends on the clinical situation

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Sinusoidal patternInterpretation of the CTG

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EFM-Sinusoidal Pattern

• Regular Oscillation of the Baseline long-term

Variability resembling a Sine wave ,with no B-

b Variability

• Has fixed cycle of 3-5 p min. with amplitude of

5-15 bpm and above but not below the

baseline.

• Should be viewed with suspicion as poor

outcome has been seen (eg Feto-maternal

haemorrhage)

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Sinusoidal pattern- distinctive smooth undulating

Sine-wave baseline with no B-b variability

• 0.3 % (Young 1980)

• cord compression

• hypovolemia

• ascites

• idiopathic(fetal thumb sucking)

• Analgesics

• Anaemia

• Abruption

• Mx r/v clinical situation

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EFM- Saltatory pattern

• Seen During Fetal thumb sucking.

• Could be associated with Hypoxia.

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NR CTGs

• Difficult to interpretation,leads to Increased

rate of C Section.

• 50% CTG in Labour have 1 abnormal feature

• 15-20% Nr CTGs (pathological).

• ?? To reduce CS….

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EFM-Summary

• Normal - CTG with all 4 Features

• Suspicious -one non reassuring category

and reminder are reassuring

• Pathological -2 or more non-reassuring

categories or one or more abnormal

categories.

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Caring for the Mom, Not the Monitor!

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References

• Manual Obs and Gyn. by Niswander, MD

• Fetal Monitoring RCOG UK

• CTGs RANZCOG

• Literature review articles American Family Physician

• CTG Made Easy

• D. Lata Sharma, MD, FRANZCOG, Senior Lecturer,

University Of Queensland, Australia

• Charles Kawada, M.D,Harvard Medical School

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