Monitoring in Labour

• Discuss fetal heart rate patterns using Continuous Discuss fetal heart rate patterns using Continuous Electronic Fetal Monitoring (CEFM) tracings.Electronic Fetal Monitoring (CEFM) tracings.

• Compare the evidence between EFM and Compare the evidence between EFM and structured intermittent auscultation (SIA)structured intermittent auscultation (SIA)

• Discuss relevant physiology in fetal monitoringDiscuss relevant physiology in fetal monitoring

• Describe systematic approaches in fetal Describe systematic approaches in fetal monitoring using Dr C Bravadomonitoring using Dr C Bravado

• Outline guidelines for fetal heart rate monitoring Outline guidelines for fetal heart rate monitoring using SIAusing SIA

Objectives

Perinatal outcomesPerinatal outcomes

50% reduction in neonatal seizures50% reduction in neonatal seizures (RR0.50, 95%CI 0.31-0.80)(RR0.50, 95%CI 0.31-0.80)

… … but but no significant differenceno significant difference in incidence of:in incidence of:

- long-term neurological handicap- long-term neurological handicap (RR1.74, 95%CI 0.97-3.11)(RR1.74, 95%CI 0.97-3.11)

- or perinatal mortality - or perinatal mortality (RR0.85, 95%CI 0.59-1.23)(RR0.85, 95%CI 0.59-1.23)

Obstetric outcomesObstetric outcomes

- 66% increase in C. Section rate- 66% increase in C. Section rate (RR1.66, 95%CI 1.30-2.13)(RR1.66, 95%CI 1.30-2.13)

- 16% increase in instrumental delivery- 16% increase in instrumental delivery (RR1.16, 95%CI 1.01-1.32)(RR1.16, 95%CI 1.01-1.32)

Alfiveric Z et al, Cochrane Database Syst Rev Alfiveric Z et al, Cochrane Database Syst Rev 20062006

CEFM vs. SIA

• Changes in FH rate patterns occur in response to changes Changes in FH rate patterns occur in response to changes in Oin O22, CO, CO22, hydrogen ions and arterial pressure, hydrogen ions and arterial pressure

• These changes are mediated via the vagus nerve, These changes are mediated via the vagus nerve, chemoreceptors & carotid body baroreceptorschemoreceptors & carotid body baroreceptors

• It is difficult to measure fetal oxygenation and pH It is difficult to measure fetal oxygenation and pH continuouslycontinuously

• FH rate patterns only allow FH rate patterns only allow indirectindirect assessment of fetal assessment of fetal acid-base balance. Fetal scalp sampling is required to acid-base balance. Fetal scalp sampling is required to confirm whether the fetus is hypoxic…confirm whether the fetus is hypoxic…

Hinshaw K & Ullal A. Anaes Int Care Med (Aug 2007)Hinshaw K & Ullal A. Anaes Int Care Med (Aug 2007)

Pathophysiology of FH rate changes

A systematic approach to CTG interpretation using EFMA systematic approach to CTG interpretation using EFM

DR. C. BRAVADO

Determine RiskContractions (< 5 in 10)Baseline Rate (110-150bpm)

Variability (>5)

Accelerations-reassuring

Decelerations

Overall Assessment & Plan

Few centres in Tanzania have this facility - refer to ALSOmanual for further information

““ DRDR CC BRAVADO” BRAVADO”

DDetermineetermine RRiskisk

Assess degree of “clinical riskAssess degree of “clinical risk” ” in relation to in relation to clinical outcomeclinical outcome

• HighHigh

• LowLow

A systematic approach to CTG interpretation

Comparable to TRAFFIC LIGHTS

Maternal:• Previous Caesarean section• Pre-eclampsia• Pregnancy >42 weeks • Prolonged ROM >24 hours• Diabetes• Antepartum haemorrhage• Significant medical condition – eg cardiac

Risk Factors

Fetal:• Intrauterine growth restrictionIntrauterine growth restriction• OligohydramniosOligohydramnios• Preterm labourPreterm labour• Multiple pregnancyMultiple pregnancy• Breech presentationBreech presentation

Risk Factors

IntrapartumIntrapartum• Significant meconium-stained liquorSignificant meconium-stained liquor• Abnormal FHR on auscultation Abnormal FHR on auscultation

baseline <110 or >160 bpm baseline <110 or >160 bpm any decelerations after a contractionany decelerations after a contraction

• Maternal pyrexiaMaternal pyrexia• Fresh bleeding in labourFresh bleeding in labour• Oxytocin augmentationOxytocin augmentation

Risk Factors

“ “ DR DR CC BRAVADO” BRAVADO”

A systematic approach to CTG interpretation

AssessAssess ccontraction patternontraction pattern

• Rate Rate

• Duration of contractionsDuration of contractions

• Coordinate or In-coordinate?Coordinate or In-coordinate?

• Baseline ToneBaseline Tone

““ DRDR CC BRABRAVADO”VADO”

A systematic approach to CTG interpretationA systematic approach to CTG interpretation

Baseline Rate

• Normal range 110-160bpm

• Baseline Bradycardia <110

• Baseline Tachycardia >160 bpm

BASELINE RATEBASELINE RATE

BRADYCARDIA<110BRADYCARDIA<110• Gestation > 40 weeksGestation > 40 weeks• Cord compressionCord compression• Congenital heart Congenital heart

malformationsmalformations• Drugs Drugs

eg.benzodiazepineseg.benzodiazepines

TACHYCARDIA>160TACHYCARDIA>160• Excessive fetal Excessive fetal

movementmovement• Maternal anxietyMaternal anxiety• Gestation <32 weeksGestation <32 weeks• Maternal pyrexiaMaternal pyrexia• Fetal infectionFetal infection• Chronic hypoxiaChronic hypoxia

“ “ DR DR CC BRA BRAVVADO”ADO”

A systematic approach to CTG interpretationA 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

VARIABILITYVARIABILITY

Persistent absence of or reduced Persistent absence of or reduced variability is potentially ominousvariability is potentially ominous

ReducedReduced NormalNormal

““ DRDR CC BRAVBRAVAADO”DO” A systematic approach to CTG interpretationA systematic approach to CTG interpretation

Accelerations

• Increase of at least 15 bpm above the Increase of at least 15 bpm above the baseline baseline

for at least 15 seconds for at least 15 seconds • Associated with movement or stimulationAssociated with movement or stimulation• Presence is the single best indicator of Presence is the single best indicator of

fetal fetal

well-beingwell-being• An antenatal CTG should always contain An antenatal CTG should always contain

accelerations to be considered normal. accelerations to be considered normal.

3 examples are highlighted3 examples are highlighted

ACCELERATIONS

A systematic approach to CTG A systematic approach to CTG interpretationinterpretation

• Early Early DDecelerations ecelerations mirror mirror contractionscontractions

• Fall of <60 beats from baseline Fall of <60 beats from baseline associated (almost exclusively) associated (almost exclusively) with excellent fetal outcomewith excellent fetal outcome

• True early uniform True early uniform decelerations are rare and decelerations are rare and benign and therefore not benign and therefore not significantsignificant

““ DRDR CC BRAVABRAVADDO”O”““ DRDR CC BRAVABRAVADDO”O”

A systematic approach to CTG interpretationA systematic approach to CTG interpretation

Variable Variable DDecelerationsecelerations• Most decelerations in labour are variableMost decelerations in labour are variable• Can reflect cord compressionCan reflect cord compression• ‘‘Variable’ in Variable’ in shapeshape, , depthdepth and/or and/or onsetonset• Usually benign but …. if late or deep may imply Usually benign but …. if late or deep may imply

cord prolapse or hypoxia cord prolapse or hypoxia • ‘‘Need to assess the frequency and durationNeed to assess the frequency and duration

““ DR C BRAVADR C BRAVADDO”O”““ DR C BRAVADR C BRAVADDO”O”

VARIABLE DECELERATIONSVARIABLE DECELERATIONS

COMPLICATED VARIABLES

A systematic approach to CTG interpretationA systematic approach to CTG interpretationLate 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

““ DR C BRAVADR C BRAVADDO” O”

• Begin Begin afterafter onset of onset of contractioncontraction

• Nadir (or trough) Nadir (or trough) afterafter peak of peak of contractioncontraction

• Return to baseline Return to baseline afterafter end of end of contractioncontraction

LATE DECELERATIONSLATE DECELERATIONS

Structured Intermittent Auscultation

In Active phase of labourMINIMUM OF 60 SECONDS after a

contractionDifferentiate maternal pulseEach 30 minutes in first stage of labourEach 15 minutes if any risk factorAfter each contraction while actively

pushing

If fetal heart rate persistabove 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”