Monitoring in Labour

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Monitoring in Labour
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Objectives

• Discuss fetal heart rate patterns using
  Continuous Electronic Fetal Monitoring (CEFM)
  tracings.
• Compare the evidence between EFM and structured
  intermittent auscultation (SIA)
• Discuss relevant physiology in fetal monitoring
• Describe systematic approaches in fetal
  monitoring using Dr C Bravado
• Outline guidelines for fetal heart rate
  monitoring using SIA

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CEFM vs. SIA

• Perinatal outcomes
• 50 reduction in neonatal seizures (RR0.50, 95CI
  0.31-0.80)
• but no significant difference in incidence of
• - long-term neurological handicap (RR1.74,
  95CI 0.97-3.11)
• - or perinatal mortality
  (RR0.85, 95CI 0.59-1.23)
• Obstetric outcomes
• - 66 increase in C. Section rate (RR1.66, 95CI
  1.30-2.13)
• - 16 increase in instrumental delivery (RR1.16,
  95CI 1.01-1.32)
• Alfiveric Z et al, Cochrane Database
  Syst Rev 2006

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Pathophysiology of FH rate changes

• Changes in FH rate patterns occur in response to
  changes in O2, CO2, hydrogen ions and arterial
  pressure
• These changes are mediated via the vagus nerve,
  chemoreceptors carotid body baroreceptors
• It is difficult to measure fetal oxygenation and
  pH continuously
• FH rate patterns only allow indirect assessment
  of fetal acid-base balance. Fetal scalp sampling
  is required to confirm whether the fetus is
  hypoxic
• Hinshaw K Ullal A. Anaes Int Care Med (Aug 2007)

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A systematic approach to CTG interpretation using
EFM

• DR. C. BRAVADO
• Determine Risk
• Contractions (lt 5 in 10)
• Baseline Rate (110-150bpm)
• Variability (gt5)
• Accelerations-reassuring
• Decelerations
• Overall Assessment Plan
• Few centres in Tanzania have this facility -
  refer to ALSO
• manual for further information

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DR C BRAVADO
A systematic approach to CTG interpretation

• Determine Risk
• Assess degree of clinical risk in relation to
  clinical outcome
• High
• Low

Comparable to TRAFFIC LIGHTS
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Risk Factors

• Maternal
• Previous Caesarean section
• Pre-eclampsia
• Pregnancy gt42 weeks
• Prolonged ROM gt24 hours
• Diabetes
• Antepartum haemorrhage
• Significant medical condition eg cardiac

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Risk Factors

• Fetal
• Intrauterine growth restriction
• Oligohydramnios
• Preterm labour
• Multiple pregnancy
• Breech presentation

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Risk Factors

• Intrapartum
• Significant meconium-stained liquor
• Abnormal FHR on auscultation
• baseline lt110 or gt160 bpm
• any decelerations after a contraction
• Maternal pyrexia
• Fresh bleeding in labour
• Oxytocin augmentation

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DR C BRAVADO

• A systematic approach to CTG interpretation
• Assess contraction pattern
• Rate
• Duration of contractions
• Coordinate or In-coordinate?
• Baseline Tone

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DR C BRAVADO

• A systematic approach to CTG interpretation
• Baseline Rate
• Normal range 110-160bpm
• Baseline Bradycardia lt110
• Baseline Tachycardia gt160 bpm

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BASELINE RATE

• BRADYCARDIAlt110
• Gestation gt 40 weeks
• Cord compression
• Congenital heart malformations
• Drugs eg.benzodiazepines

• TACHYCARDIAgt160
• Excessive fetal movement
• Maternal anxiety
• Gestation lt32 weeks
• Maternal pyrexia
• Fetal infection
• Chronic hypoxia

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DR C BRAVADO

• A systematic approach to CTG interpretation
• Variability
• The presence of normal fetal heart rate
  variability is one of the best indicators of
  intact integration between the central nervous
  system and the heart of the fetus
• Normal 5 bpm

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VARIABILITY
Persistent absence of or reduced variability is
potentially ominous
Reduced Normal
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DR C BRAVADO

• A systematic approach to CTG interpretation
• Accelerations

• Increase of at least 15 bpm above the baseline
• for at least 15 seconds
• Associated with movement or stimulation
• Presence is the single best indicator of fetal
• well-being
• An antenatal CTG should always contain
  accelerations to be considered normal.

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ACCELERATIONS
3 examples are highlighted
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DR C BRAVADO

• A systematic approach to CTG interpretation
• Early Decelerations mirror contractions
• Fall of lt60 beats from baseline associated
  (almost exclusively) with excellent fetal outcome
• True early uniform decelerations are rare and
  benign and therefore not significant

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DR C BRAVADO

• A systematic approach to CTG interpretation
• Variable Decelerations
• Most decelerations in labour are variable
• Can reflect cord compression
• Variable in shape, depth and/or onset
• Usually benign but . if late or deep may imply
  cord prolapse or hypoxia
• Need to assess the frequency and duration

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VARIABLE DECELERATIONS
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COMPLICATED VARIABLES
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DR C BRAVADO

• A systematic approach to CTG interpretation
• Late Decelerations
• Associated with fetal compromise (hypoxia)
• but only in 50-60 of cases
• Ominous if associated with
• - fresh particulate meconium
• - high-risk clinical situation
• Ominous if
• - ? lag-time (peak to trough)
• - deceleration is slow to recover

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LATE DECELERATIONS

• Begin after onset of contraction
• Nadir (or trough) after peak of contraction
• Return to baseline after end of contraction

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Structured Intermittent Auscultation

• In Active phase of labour
• MINIMUM OF 60 SECONDS after a contraction
• Differentiate maternal pulse
• Each 30 minutes in first stage of labour
• Each 15 minutes if any risk factor
• After each contraction while actively pushing

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• If fetal heart rate persist
• above 180 bpm or below 100 bpm
• plan delivery
• If the cervix is fully dilated and the fetal head
  is not more than 1/5 above the symphysis pubis
  (or at station 0 or below) deliver by vacuum
• If the cervix is not fully dilated or the fetal
  head is more than 1/5 above the symphysis pubis
  (or above station 0) deliver by cesarean section
• Managing obstetric complications, WHO

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