What are the NICE guidelines for using cardiotocography (CTG) to monitor labour in women with risk factors for fetal compromise?

CTG Monitoring in Labour for Women with Risk Factors

For women with risk factors for fetal compromise during labour, continuous cardiotocography (CTG) monitoring should be used rather than intermittent auscultation, with monitoring frequency and delivery timing determined by the specific risk factors present, particularly umbilical artery Doppler findings. 1

Indications for Continuous CTG in High-Risk Labour

Continuous electronic fetal monitoring should be employed when high-risk conditions are present, including: 2

• Fetal growth restriction with abnormal Doppler studies 2, 1
• Maternal conditions: hypertension, diabetes, cardiac disease, chorioamnionitis 2
• Pregnancy complications: post-term pregnancy, oligohydramnios, previous stillbirth 2
• Intrapartum factors: oxytocin augmentation, epidural analgesia, meconium-stained fluid 2
• Abnormalities detected on intermittent auscultation 2

CTG Monitoring Frequency Based on Risk Stratification

For FGR with Normal Umbilical Artery Doppler

• Monitor every 2 weeks antenatally 1
• Continuous CTG throughout labour 2
• Plan delivery at 38-39 weeks if estimated fetal weight 3rd-10th percentile 2, 1

For FGR with Decreased Diastolic Flow (Abnormal but Present End-Diastolic Velocity)

• Weekly CTG monitoring antenatally 2, 1
• Weekly umbilical artery Doppler assessment 2
• Continuous CTG throughout labour with induction of labour recommended 2
• Deliver at 37 weeks gestation 2, 1

For FGR with Absent End-Diastolic Velocity

• CTG monitoring 2-3 times per week antenatally 2
• Twice-weekly CTG and/or biophysical profile 2
• Continuous CTG throughout labour 2
• Strong consideration for cesarean delivery 2
• Deliver at 33-34 weeks gestation 2, 1

For FGR with Reversed End-Diastolic Velocity

• CTG monitoring 1-2 times per day with hospitalization 2, 1
• Administer antenatal corticosteroids 2
• Cesarean delivery strongly recommended 2
• Deliver at 30-32 weeks gestation 2, 1

Interpretation Framework During Labour

Use the systematic DR C BRAVADO approach for CTG interpretation: 2

• DR (Determine Risk): Assess maternal and fetal risk factors
• C (Contractions): Evaluate rate, frequency, duration, and intensity
• BRA (Baseline Rate): Normal 110-160 bpm; bradycardia <110 bpm; tachycardia >160 bpm 2
• V (Variability): Moderate variability (6-25 bpm) is reassuring; absent or minimal variability with decelerations increases risk of fetal acidosis 2
• A (Accelerations): Presence indicates fetal well-being (≥15 bpm for ≥15 seconds) 2
• D (Decelerations): Classify as early, variable, late, or prolonged 2

Management of Abnormal CTG Patterns

Category II (Indeterminate) Tracings

• Discontinue oxytocin if being administered 3
• Perform vaginal examination to exclude cord prolapse 4
• Check maternal vital signs 4
• Administer IV fluids and consider maternal repositioning 4, 3
• Increase surveillance frequency 3
• Prepare for expedited delivery if patterns persist or worsen 3

Category III (Abnormal) Tracings or Late Decelerations with Absent Variability

• Immediate preparation for expeditious delivery 4
• Late decelerations represent uteroplacental insufficiency and fetal hypoxemia 4
• Do not delay for fetal scalp stimulation when late decelerations are present 4
• Cesarean delivery is typically required 4

Integration with Other Monitoring Modalities

CTG should never be used as the sole form of surveillance in high-risk pregnancies: 2

• Serial umbilical artery Doppler assessment to monitor for deterioration 2, 1
• Biophysical profile or modified biophysical profile 2, 1
• Consider ductus venosus Doppler when umbilical artery shows absent/reversed flow 2
• Middle cerebral artery Doppler to assess for brain-sparing physiology 3

Critical Pitfalls to Avoid

Do not use intermittent auscultation in women with identified risk factors - this requires one-to-one nursing care and is inappropriate when continuous monitoring is indicated. 2

Do not perform routine admission CTG in low-risk women - this increases intervention rates without improving neonatal outcomes. 2

Recognize that CTG has a high false-positive rate (60%) but excellent negative predictive value - a normal CTG is highly reassuring, but abnormal patterns require clinical correlation and often additional testing. 5

Understand that continuous CTG increases cesarean section rates (NNH = 20) and instrumental vaginal births (NNH = 33) but reduces neonatal seizures (NNT = 661) without demonstrable reduction in cerebral palsy or perinatal mortality. 2, 6

Do not rely solely on pattern recognition - understand the underlying physiology of fetal heart rate changes to avoid unnecessary operative interventions while maintaining vigilance for true fetal compromise. 5

Preterm Considerations

When delivery is anticipated or occurs preterm based on CTG findings:

• Administer antenatal corticosteroids if delivery anticipated before 33 6/7 weeks or between 34 0/7 and 36 6/7 weeks without prior course 2
• Administer intrapartum magnesium sulfate for neuroprotection if <32 weeks gestation 2