Cardiotocography Monitoring Guidelines for Fetal Growth Restriction

Key Recommendations

• The American College of Obstetricians and Gynecologists recommends cardiotocography (CTG) monitoring weekly after viability for fetal growth restriction (FGR) without absent or reversed end-diastolic velocity in the umbilical artery, with increased frequency when FGR is complicated by absent or reversed end-diastolic velocity or other comorbidities 1
• Weekly CTG testing is recommended after viability for FGR without absent or reversed end-diastolic velocity, with an increase in frequency to twice weekly or more when FGR is complicated by absent or reversed end-diastolic velocity or other comorbidities 1, 2

CTG Monitoring Frequency

• The American College of Obstetricians and Gynecologists suggests CTG monitoring every 2 weeks with normal umbilical artery Doppler, at least weekly with abnormal umbilical artery Doppler, 1-2 times per day with absent end-diastolic velocity, and 1-2 times per day with reversed end-diastolic velocity 2, 3

Integration with Other Monitoring Modalities

• CTG should be used in conjunction with umbilical artery Doppler assessment in FGR, with serial umbilical artery Doppler assessment to assess for deterioration once FGR is diagnosed 2, 3

Delivery Timing

• The American College of Obstetricians and Gynecologists recommends delivery at 38-39 weeks for FGR with normal umbilical artery Doppler and estimated fetal weight between 3rd-10th percentile, at 37 weeks for FGR with decreased diastolic flow or severe FGR, at 33-34 weeks for FGR with absent end-diastolic velocity, and at 30-32 weeks for FGR with reversed end-diastolic velocity 2

Mode of Delivery

• Cesarean delivery should be considered for pregnancies with FGR complicated by absent or reversed end-diastolic velocity, based on the entire clinical scenario 2
• Induction of labor with continuous CTG monitoring is recommended if umbilical end-diastolic flow is present 3

Common Pitfalls to Avoid

• Relying solely on CTG for surveillance without integrating Doppler studies, using CTG as the only form of surveillance in high-risk pregnancies, failing to increase monitoring frequency when deterioration in Doppler parameters is observed, and delaying delivery when significant abnormalities are detected on CTG in the context of FGR 1, 2, 3

Interpretación del Cardiotocograma (CTG)

Parámetros clave para evaluar en el CTG

• La línea de base normal de la frecuencia cardíaca fetal se encuentra entre 110-160 latidos por minuto, según la American Journal of Obstetrics and Gynecology 4.
• Incrementos transitorios de la frecuencia cardíaca fetal de al menos 15 latidos por minuto durante 15 segundos o más son considerados aceleraciones, y su presencia es un signo tranquilizador de bienestar fetal, según la American Journal of Obstetrics and Gynecology 4.
• Desaceleraciones tempranas, que son disminuciones graduales de la frecuencia cardíaca fetal que coinciden con el inicio y fin de la contracción, son generalmente benignas, según la American Journal of Obstetrics and Gynecology 4.

Consideraciones especiales en restricción del crecimiento fetal (RCF)

• En fetos con restricción del crecimiento fetal, el cardiotocograma anormal casi invariablemente precede a las anomalías del Doppler del ductus venoso después de las 32 semanas, según la American Journal of Obstetrics and Gynecology 5.
• Se recomienda monitorización semanal con cardiotocograma después de la viabilidad para restricción del crecimiento fetal sin flujo diastólico ausente o reverso en la arteria umbilical, según la American Journal of Obstetrics and Gynecology 6.
• La frecuencia de monitorización debe aumentarse cuando la restricción del crecimiento fetal se complica con flujo diastólico ausente o reverso en la arteria umbilical, según la American Journal of Obstetrics and Gynecology 6.