Recent NICE Guidelines for Cardiotocography (CTG) Monitoring in High-Risk Pregnancies
CTG monitoring should be performed weekly after viability for fetal growth restriction (FGR) without absent or reversed end-diastolic velocity in the umbilical artery, with increased frequency to twice weekly or more when FGR is complicated by absent or reversed end-diastolic velocity or other comorbidities. 1
CTG Monitoring Frequency Based on Risk Factors
- For high-risk pregnancies with normal umbilical artery Doppler, CTG monitoring is recommended every 2 weeks 1
- For high-risk pregnancies with abnormal umbilical artery Doppler, CTG monitoring should be performed at least weekly 1
- For pregnancies with absent end-diastolic velocity, CTG monitoring should be increased to 1-2 times per day 1
- For pregnancies with reversed end-diastolic velocity, CTG monitoring should be performed 1-2 times per day 1
Integration with Other Monitoring Modalities
- CTG should be used in conjunction with umbilical artery Doppler assessment in FGR 1
- Serial umbilical artery Doppler assessment should be performed to assess for deterioration once FGR is diagnosed 1
- The biophysical profile, modified biophysical profile, and duplex Doppler velocimetry are the main ultrasound-based modalities to determine fetal health 2
Delivery Timing Based on CTG and Doppler Findings
- For FGR with normal umbilical artery Doppler and estimated fetal weight between 3rd-10th percentile: Delivery at 38-39 weeks 1
- For FGR with decreased diastolic flow or severe FGR: Delivery at 37 weeks 1
- For FGR with absent end-diastolic velocity: Delivery at 33-34 weeks 1
- For FGR with reversed end-diastolic velocity: Delivery at 30-32 weeks 1
Mode of Delivery Considerations
- Cesarean delivery should be considered for pregnancies with FGR complicated by absent or reversed end-diastolic velocity 1, 3
- Abnormal fetal surveillance, such as abnormal CTG or ductus venosus Doppler, is an indication for cesarean section delivery 3
- Induction of labor with continuous CTG monitoring is recommended if umbilical end-diastolic flow is present 3
Effectiveness of CTG Monitoring
- Despite widespread use, there is limited evidence that antenatal testing decreases the risk for fetal death in low-risk pregnancies 2
- Computerized CTG (cCTG) has shown a significant reduction in perinatal mortality compared to traditional visual CTG (RR 0.20,95% CI 0.04 to 0.88) 4
- No single antenatal test has been shown to be superior, but all have high negative predictive values 2
Common Pitfalls to Avoid
- Relying solely on CTG for surveillance without integrating Doppler studies 1
- Using CTG as the only form of surveillance in high-risk pregnancies 1
- Failing to increase monitoring frequency when deterioration in Doppler parameters is observed 1
- Delaying delivery when significant abnormalities are detected on CTG in the context of FGR 1
- The positive predictive value for intrapartum fetal hypoxia is approximately only 30% with a high false-positive rate of 60% 5
International Consensus on CTG Monitoring
- Weekly or twice-weekly fetal testing has become the standard practice in high-risk pregnancies 2
- The timing for the initiation of assessments of fetal well-being should be tailored based on the risk for stillbirth and the likelihood of survival with intervention 2
- Five of six international guidelines recommend low-dose aspirin for prevention of small for gestational age (SGA) 2
CTG monitoring remains a cornerstone of fetal surveillance in high-risk pregnancies despite its limitations. When combined with Doppler studies and other fetal assessment modalities, it provides valuable information for clinical decision-making regarding timing and mode of delivery to optimize maternal and fetal outcomes.