Electronic Fetal Monitoring

CONSENSUS STATEMENT


 

 
CONTENTS

FOREWORD
PREFACE
WORKING COMMITTEE
CONSENSUS STATEMENT

 

ANTEPARTUM ELECTRONIC FETAL HEART RATE MONITORING

I. Introduction
II. Indications

A. Maternal medical disorder
B. Bad obstetric history
C. Post-date pregnancy
D. Fetal indications

III. Procedure
IV. Interpretation
V. Management

INTRAPARTUM FETAL HEART RATE MONITORING 

I. Introduction
II. Upon admission in labour

A. EFM - How long & for whom? 
B. Interpretation 
C. Management

III. Patients in labour

A. Intermittent Monitoring 
B. Auscultation
C. Patients refusing EFM 
D. Continuous EFM 
E. Interpretation
F. Management

REFERENCES


FOREWORD

There is certainly a need for standard approaches to the management of many clinical conditions.

Clinicians have been writing clinical practice guidelines (CPG) for several years now on topics which are managed diversely. This CPG on electronic fetal monitoring (EFM) is timely and represents the hard work of several people. It is commendable effort to bring some uniformity of approach throughout the country.

I am concerned that CPGs such as this should be actively used and should not be just another academic exercise.

I Commend this excellent work for wide usage for both the private and public services.

Datu Dr. Mohd.Taha bin Arif
Director General of Health, Malaysia

 

PREFACE

Consensus on Electronic Fetal Monitoring

The introduction of Electronic Fetal Monitoring (EFM) into obstetric practice in the 1970's created a major shift in the approach to the management of patients in labour and also in ante-natal assessments.

However the medical community was not particularly discerning when this technology was introduced as the scientific evidence of its validity was scant. There has been much attempt in the last few years to bridge the gap between evidence and practice.

This paper was developed to document the current position of EFM in everyday obstetric practice. Admittedly the scientific evidence for some area of use is still thin.

Thus this paper outlines the area where it is clearly useful and also describes  the generally accepted approach to EFM in labour in Malaysia and elsewhere.

Various individuals have contributed significantly towards the preparation of this paper which went through nine meetings.

Dato' Dr. Alex Matthews
Chairman
Consensus Committee on EFM Guidelines

WORKING COMMITTEE

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Committee Members 

Dato' Dr. Alex Matthews      Chairman
Senior Consultant and Head
Dept. of O & G
Hospital Kuala Lumpur
  
Assoc. Prof. Patrick Chia Co-Chairman
Consultant
Dept. of O & G
International Medical University
Seremban
  
Dr. T.P.Baskaran Secretary
Obstetrician & Gynaecologist
Dept. of O & G
Hospital Kuala Lumpur
  
Assoc. Prof. Dr. Muhammad Abdul Jamil
Consultant
Dept. of O & G
Hospital UKM, Kuala Lumpur
  
Dr.P.Boopalan
President
College of Obstetrician & Gynaecologists
Academy of Medicine of Malaysia
  
Dato' Dr. Johan A.M. Thambu
Consultant Obstetrician & Gynaecologist
Tawakal Specialist Centre
Kuala Lumpur
  
Dr. Michael J Samy
Consultant Obstetrician & Gynaecologist
Tawakal Specialist Centre
Kuala Lumpur
  
Dr. S. Rachagan
Consultant Obstetrician & Gynaecologist
Subang Jaya Medical Centre
Petaling Jaya
  
Dato' Dr. Lim Ngok Ling
Consultant
Dept. of Paediatrics
Selayang Hospital, Selangor
  
Prof. C.T. Lim
Consultant
Dept. of Paediatrics
University Hospital
Kuala Lumpur
  
Dr. Cheah Fook Choe
Clinic Specialist
Dept. of Paediatrics
Hospital UKM, Kuala Lumpur

 


CONSENSUS STATEMENT ON ELECTRONIC FETAL MONITORING

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The wellbeing of the fetus is one of the main concerns in obstetric care. The assessment of fetal wellbeing is widely practised by measuring the fetal heart rate and monitoring its patterns1,2,3.

Electronic fetal monitoring (EFM) is a non-invasive method of assessing fetal wellbeing. The use of EFM has been shown to reduce the risk of neonatal seizures in high-risk pregnancies4. On the other hand, there is no evidence for the routine use of EFM in low-risk pregnancies when adequate clinical monitoring (including intermittent auscultation by trained staff) is available4.

EFM also provides a permanent documentation of fetal heart rate and its patterns
5,6.

The usefulness of EFM however, is limited by inter-observer variation in the interpretation of its tracings
7,8. Therefore, EFM must be used together with other modalities in the assessment of fetal wellbeing9.

EFM Guidelines:
We propose the following EFM guidelines based on current pratice: 
- Antepartum electronic fetal heart rate monitoring 
- Intrapartum electronic fetal heart rate monitoring

 

ANTEPARTUM ELECTRONIC FETAL HEART RATE MONITORING

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I. INTRODUCTION:
There is no strong evidence to support EFM use in the antepartum period4,10. However, EFM is widely used in the assessment of fetal health, particularly in high-risk pregnancies as there are no other objective methods of documenting the fetal state.
EFM if adopted should be done no earlier than 32 completed weeks of gestation. It is used in any patient at risk of developing decreased utero-placental function. The following is a guide.

II. INDICATIONS:

A. Maternal medical disorders

1. Pregnancy induced hypertension
2. Diabetes (gestational or insulin dependent) 
3. Anaemia and other haematological diseases 
4. Chronic hypertension 
5. Cardiac disease
6. Collagen disease 
7. Renal disease
8. Thyroid disease

B. Bad obstetric history
C. Post-date pregnancy
D. Fetal indications

1. Reduced fetal movements 
2. Suspected IUGR
3. Abnormal FHR by auscultation 
4. Multiple pregnancy
5. Rhesus iso-immunisation

III. PROCEDURE:

  1. Place the patient in the left lateral recumbent position.
  2. Record the patient's name, hospital record/registration number, date and time on the EFM strip.
  3. Place and adjust the external tocodynamometer and ultrasound transducer to obtain the best possible tracing.
  4. Instruct the patient to record fetal movements on the monitor tracing using the event marker.
  5. Observe the EFM tracing until the criteria for a reactive test are met (a minimum of 20 minutes and a maximum of 60 minutes).
  6. In the event of lack of fetal movement, apply stimulation (for example: using the fetal acoustic stimulator).
  7. Record any relevant clinical information on the EFM tracing, for example the blood pressure, temperature,maternal heart rate, loss of contact, and changes in maternal position.
  8. Keep the EFM tracings in the patient's notes.

IV. INTERPRETATION 11

1. Normal/Reassuring Trace
    - Baseline heart rate 110-150 bpm 
    - Baseline variability 10-25 bpm
    - At least 2 accelerations (>15 beats for> 15 seconds)
        in 20 minutes. 
    - No decelerations.
2. Suspicious/Equivocal Trace. 
    - Baseline heart rate 150-170 bpm or 100-110 bpm;  
    - Reduced baseline variability (5-10 bpm for 
                  >40 minutes) 
    - Absence of accelerations for >40 minutes 
    - Sporadic deceleration of any type.
  3. Abnormal/Pathological Trace
   - Baseline heart rate <100 bpm or > 170 bpm  
   - Silent Pattern (<5 bpm) for >40 minutes  
   - Sinusoidal pattern (oscillation frequency 
            = 2-5 cycles/min, amplitude of 5-15 bpm) for 
            >40 minutes with no accelerations and no area 
            of normal baseline variability 
   - Repeated late, prolonged (> 1 minute) and severe 
            variable (>40 bpm) decelerations.

V. MANAGEMENT:

  1. Normal/Reassuring Trace - repeat and/or estimate the amniotic fluid index (AFI) if considered necessary according to the clinical situation and indication for testing.
  2. Suspicious/Equivocal Trace - continue for up to 60 minutes to determine the presence of fetal rest/activity cycles. Consider further evaluation according to the clinical situation e.g. fetal acoustic stimulation, AFI, biophysical profile (BPP), Doppler ultrasound blood velocity waveform.
  3. Abnormal/Pathological Trace - deliver if clinically appropriate. Further evaluation/monitoring if not appropriate to deliver.

 

ANTEPARTUM FETAL MONITORING IN HIGH RISK PREGNANCIES

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INTRAPARTUM ELECTRONIC FETAL HEART RATE MONITORING

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I. INTRODUCTION:

It is well established that EFM has value in the intrapartum period in the assessment of the fetus12. However, it is of value only when used together with all other available information concerning the mother and the fetus10. Furthermore those who use EFM must be trained individuals, who are able to recognise its benefits as well as its limitations. It is recommended that all labour and delivery units should have some form of fetal monitoring. '

II. UPON ADMISSION IN LABOUR

A. EFM - How long and for whom?
Fetal heart rate monitoring is commonly recorded for
20 minutes. It is recommended for high-risk patients and
for those who are low-risk presenting late in labour (where EFM is available). Discontinue monitoring only if the tracing is reassuring or normal.

THE HIGH-RISK CONDITIONS INCLUDE:

a) Pre-existing obstetrical/medical factors: 

1. Age >35 or <16. 
2. Diabetes
3. Chronic hypertension 
4. Cardiac disease
5. Rhesus iso-immunisation
6. Sickle cell disease. and other haemoglobinopathies
7. Previous Caesarean section 
8. Previous stillbirth 
9. Renal disease
10. Active pulmonary disease
11. Medical conditions requiring pharmacological therapy
12. Collagen/vascular disease 
13. Seizure disorder
14. Substance abuse
15. Parity greater than 5

b) Prenatal and early intrapartum factors:

1. Anaemia
2. Pregnancy induced hypertension
3. Polyhydramnios or oligohydramnios 
4. Clinical evidence of intrauterine growth restriction 
5. Vaginal bleeding
6. Abnormal antepartum fetal testing 
7. Induction of labour 
8. No prenatal care
9. Premature rupture of membranes 
10. Premature labour
11. Meconium-stained amniotic fluid
12. Abnormal fetal heart tones by auscultation 
13. Pyelonephritis
14. Breech or other abnormal presentation 
15. Multiple pregnancy
16. Gestational age <37 weeks or >42 weeks
17. Estimated fetal weight less than 2500 grams or greater than 4000 grams
18. Any acute or chronic maternal illness. which would increase the risk to the mother or infant

B. INTERPRETATION11,13    

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 
    - No decelerations
    - Moderate tachycardia/bradycardia and accelerations
b) Suspicious/Equivocal Trace
    - Absence of accelerations for >40 minutes
    - Baseline heart rate> 150 bpm or <110 bpm;
    - Reduced baseline variability or silent pattern 
         (<5 bpm for >40 minutes) although 
         normal baseline (110-150 bpm) 
    - Sporadic deceleration of any type.
c) Abnormal/Pathological Trace
    - Poor baseline variability (<5 bpm) with normal 
         base line heart rate (110- 150 bpm) 
         with no accelerations
    - Repeated late decelerations and/or complicated 
         variable decelerations
    - Baseline heart rate <100 bpm or prolonged 
         bradycardia (i.e. drop in baseline fetal 
         heart rate <100 bpm for >3 minutes or 
         <80 bpm for >2 minutes) for more than 
         10 minutes

C. MANAGEMENT:

  1. Normal/Reassuring trace - risk of fetal hypoxia in spontaneous labour is low for at least the next 2-3 hours of low-risk labour. However, in high-risk cases, continuous EFM may be warranted.
  2. Suspicious/Equivocal Trace - continue EFM but amniotomy should be performed. Fetal scalp blood pH is considered if there is meconium stained liquor, to determine subsequent management or deliver if indicated. When scalp pH testing is unavailable, continuous EFM may be considered if the liquor is clear.
  3. Abnormal/Pathological Trace - amniotomy is performed to observe the liquor, and subsequent management is determined as in (b) above. Deliver if fetal scalp pH is required but not obtainable i.e. if cervix not sufficiently dilated or equipment not available.

III. PATIENTS IN LABOUR:

A. INTERMITTENT MONITORING

1.  The baseline monitor strip must be reassuring. Stable baseline FHA 110-150 bpm with average long-term variability and NO decelerations. Accelerations are additional reassuring feature.
2. The patient should not have risk factors present.
3. A fetal monitor strip should be obtained for at least 10 minutes every hour. Discontinue only if the tracing is reassuring. If abnormal findings are detected continuous monitoring should be instituted when sufficient monitors are available.


B. AUSCULTATION:

1. If this technique is used. personnel should recognize its limitations.
2. There are no evidence based criteria available to detect fetal distress or fetal well being using auscultation alone.
3. FHR should be auscultated in relationship to uterine contractions (UC). Auscultation of FHR for 60 seconds should be done during and immediately following a contraction.
4. Recommended auscultation intervals:

        a. Every 60 minutes in early labour
        b. Every 30 minutes in active labour
        c. Every 15 minutes during second stage
5. When possible monitor patient electronically if abnormal FHR is detected.


C. PATIENTS REFUSING ELECTRONIC FETAL MONITORING:

1. Explain nature of procedure including risks versus benefits of electronic fetal monitoring.
2. Document the explanation given.
3. Document if patient refuses to be monitored.


D. CONTINUOUS EFM:

This is recommended in high-risk patients and those who develop intrapartum factors, which include:
1. Prolonged latent phase
2. Dysfunctional labour
3. Secondary arrest of cervical dilatation.
4. Prolonged second stage
5. Augmentation of labour
6. Temperature greater than 38 degrees Celsius
7. Significant variation of maternal blood pressure from previously recorded values.
8. Elevation of maternal blood pressure of greater than 30 mm Hg systolic or 15 mm Hg diastolic.
9. Meconium stained liquor
10. Amnionitis
11. Placenta abruption
12. Placenta praevia
13. Bleeding of unknown cause
14. Epidural/Spinal anaesthesia


E. INTERPRETATION
11,13  

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)
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
c) 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


F. MANAGEMENT:

a) Normal/Reassuring Trace - risk of fetal hypoxia in spontaneous labour is low. Manage normally.
b) Suspicious/Equivocal Trace - continue EFM but amniotomy should be performed +/- fetal scalp blood pH if meconium stained liquor is present.
c) Abnormal/Pathological Trace - amniotomy and consider 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.

 

INTRAPARTUM FETAL MONITORING

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REFERENCES

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1. Lee CY, Diloreto PC, O'Lane JM. A study of fetal heart rate acceleration patterns. Obstet Gl,lnaeco/1975; 45: 142-146.
2. Flynn AM, Kelly J. Evaluation of fetal wellbeing by antepartum fetal heart monitoring. Sf Med J 1977; 1: 936-939.
3. Rayburn WF, Duhring JL, Donaldson M. A study of fetal acceleration tests. Am J Obstet Gl,lneco/1978; 132: 33-35.
4. Macdonald D, Grant A, Sheridan-Pereira M et a/.. The Dublin randomised controlled trial of intrapartum fetal heart rate monitoring. Am J Obstet Gl,lneco/ 1985; 152: 524-539.
5. Spencer JAD. Clinical overview of cardiotocography. Sf J Obstet Gl,lnaeco/1993;100(supp 9): 4-7.
6. van Wijngaarden WJ. Intrapartum fetal surveiliance-CTG, acid-base and FECG. In: O'Brien PMS, editor. The Yearbook of Obstetrics and Gynaecology, volume 6. London. RCOG Press, 1998: 93-105.
7. Nielsen PV, Stigsby B, Nickelson C, Nim J. Intra and Inter-observer variability in the assessment of intrapartum cardiotocograms. Acta Obstet Gl,lnaeco/ Scand 1987; 66: 421-424.
8. Lotgering FK, Wallenberg HCS, Schouten HJA. Interobserver and intraobserver variation in the assessment of antepartum cardiotocograms. Am J Obstet Gl,lneco/1982; 144: 701-705.
9. Guidelines for the use of fetal monitoring (FIGO news). Int. J Gynecol Obstet 1987; 25: 159-167.
10.  Chua S, Arulkumaran S. Intrapartum Fetal Monitoring. In: Arulkumaran S, Ng SC, eds. Current Issues in Obstetrics & Gynaecology. Singapore: Oxford University Press 1996; 233-257.
11. Gibb D, Arulkumaran S. Control of the fetal heart. In: Gibb D, Arulkumaran S, eds. Fetal Monitoring in Practice. Oxford: Butterworth-Heinemann 1992; 22-39.
12. Symonds EM. Litigation and the cardiotocogram. Sf J Obstet Gl,lnaeco/1993; 100(supp 9): 8-9.
13. Fetal Trace Interpretation. In: Arulkumaran S, Ingemarsson I, Montan S, Gibb D, Paul RH, Schiffrin BS et a/, eds. Traces of you. Germany: Hewlett-Packard 1993.