Monitoring in Labour

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

Perinatal outcomes 50% reduction in neonatal seizures (RR0.50, 95%CI ) … but no significant difference in incidence of: - long-term neurological handicap (RR1.74, 95%CI ) - or perinatal mortality (RR0.85, 95%CI ) Obstetric outcomes - 66% increase in C. Section rate (RR1.66, 95%CI ) - 16% increase in instrumental delivery (RR1.16, 95%CI ) Alfiveric Z et al, Cochrane Database Syst Rev 2006 Alfiveric Z et al, Cochrane Database Syst Rev 2006 CEFM vs. SIA

Changes in FH rate patterns occur in response to changes in O 2, CO 2, hydrogen ions and arterial pressureChanges in FH rate patterns occur in response to changes in O 2, CO 2, hydrogen ions and arterial pressure These changes are mediated via the vagus nerve, chemoreceptors & carotid body baroreceptorsThese changes are mediated via the vagus nerve, chemoreceptors & carotid body baroreceptors It is difficult to measure fetal oxygenation and pH continuouslyIt 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…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) Pathophysiology of FH rate changes

A systematic approach to CTG interpretation using EFM DR. C. BRAVADO Determine Risk Contractions (< 5 in 10) Baseline Rate ( bpm) Variability (>5) Accelerations-reassuring Decelerations Overall Assessment & Plan Few centres in Tanzania have this facility - refer to ALSO manual for further information

“ DR C BRAVADO” Determine Risk Assess degree of “clinical risk” in relation to clinical 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

Intrapartum Significant meconium-stained liquorSignificant meconium-stained liquor Abnormal FHR on auscultationAbnormal FHR on auscultation  baseline 160 bpm  any decelerations after a contraction Maternal pyrexiaMaternal pyrexia Fresh bleeding in labourFresh bleeding in labour Oxytocin augmentationOxytocin augmentation Risk Factors

“ DR C BRAVADO” A systematic approach to CTG interpretation Assess contraction pattern Assess contraction pattern RateRate Duration of contractionsDuration of contractions Coordinate or In-coordinate?Coordinate or In-coordinate? Baseline ToneBaseline Tone

“ DR C BRAVADO” A systematic approach to CTG interpretation Baseline Rate Normal range bpm Baseline Bradycardia <110 Baseline Tachycardia >160 bpm

BASELINE RATE BRADYCARDIA<110 BRADYCARDIA<110 Gestation > 40 weeksGestation > 40 weeks Cord compressionCord compression Congenital heart malformationsCongenital heart malformations Drugs eg.benzodiazepinesDrugs eg.benzodiazepines TACHYCARDIA>160 TACHYCARDIA>160 Excessive fetal movementExcessive fetal movement Maternal anxietyMaternal anxiety Gestation <32 weeksGestation <32 weeks Maternal pyrexiaMaternal pyrexia Fetal infectionFetal infection Chronic hypoxiaChronic hypoxia

“ 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

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

“ DR C BRAVADO” A systematic approach to CTG interpretation A systematic approach to CTG interpretation Accelerations Increase of at least 15 bpm above the baselineIncrease of at least 15 bpm above the 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 fetalPresence is the single best indicator of fetal well-being well-being An antenatal CTG should always contain accelerations to be considered normal.An antenatal CTG should always contain accelerations to be considered normal.

3 examples are highlighted ACCELERATIONS

A systematic approach to CTG interpretation Early Decelerations mirror contractionsEarly Decelerations mirror contractions Fall of <60 beats from baseline associated (almost exclusively) with excellent fetal outcomeFall of <60 beats from baseline associated (almost exclusively) with excellent fetal outcome True early uniform decelerations are rare and benign and therefore not significantTrue early uniform decelerations are rare and benign and therefore not significant “ DR C BRAVADO”

A systematic approach to CTG interpretation Variable Decelerations Most decelerations in labour are variableMost decelerations in labour are variable Can reflect cord compressionCan reflect cord compression ‘Variable’ in shape, depth and/or onset‘Variable’ in shape, depth and/or onset Usually benign but …. if late or deep may imply cord prolapse or hypoxiaUsually benign but …. if late or deep may imply cord prolapse or hypoxia ‘Need to assess the frequency and duration‘Need to assess the frequency and duration “ DR C BRAVADO”

VARIABLE DECELERATIONS

COMPLICATED VARIABLES

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 “ DR C BRAVADO”

Begin after onset of contractionBegin after onset of contraction Nadir (or trough) after peak of contractionNadir (or trough) after peak of contraction Return to baseline after end of contractionReturn to baseline after end of contraction LATE DECELERATIONS

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

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”