What is the management for a fetus with restricted growth and abnormal heart rate?

Management of Fetal Growth Restriction with Abnormal Heart Rate

For a fetus with restricted growth and abnormal heart rate, immediate delivery is indicated if umbilical artery Doppler shows absent or reversed end-diastolic velocity, with cesarean section strongly recommended based on the severity of compromise. 1, 2

Initial Assessment and Risk Stratification

The management algorithm depends critically on:

• Gestational age at diagnosis 1
• Severity of growth restriction (estimated fetal weight <3rd percentile vs. 3rd-10th percentile) 1
• Umbilical artery Doppler findings (normal, decreased diastolic flow, absent end-diastolic velocity [AEDV], or reversed end-diastolic velocity [REDV]) 1, 3
• Nature of heart rate abnormality (non-reactive vs. ominous cardiotocography pattern) 1

Surveillance Protocol Based on Doppler Findings

Normal Umbilical Artery Doppler

• Weekly cardiotocography after viability 1
• Umbilical artery Doppler every 2 weeks 3
• Cardiotocography should not be used as the only form of surveillance 1

Decreased Diastolic Flow (but not absent/reversed)

• Weekly umbilical artery Doppler evaluation 1, 3
• Twice-weekly cardiotocography and/or biophysical profile 1
• Increased surveillance frequency compared to normal Doppler 1

Absent End-Diastolic Velocity (AEDV)

• Doppler assessment 2-3 times per week 1, 3
• Daily cardiotocography (at least once daily, preferably 1-2 times) 1, 3
• Consider hospitalization for continuous monitoring 1, 2
• AEDV indicates severe placental insufficiency with obliteration of approximately 70% of placental tertiary villi arteries 2

Reversed End-Diastolic Velocity (REDV)

• Hospitalization is mandatory 1, 3
• Cardiotocography at least 1-2 times per day 1, 3
• Immediate administration of antenatal corticosteroids if <34 weeks 1, 3
• Consideration of immediate delivery depending on gestational age and complete clinical picture 1, 3

Timing of Delivery

FGR with Normal Doppler

• Deliver at 38-39 weeks when estimated fetal weight is between 3rd-10th percentile 1, 3
• Deliver at 37 weeks if estimated fetal weight <3rd percentile (severe FGR) 1, 3

FGR with Decreased Diastolic Flow

• Deliver at 37 weeks of gestation 1, 3
• This applies to umbilical artery Doppler with decreased diastolic flow but without absent/reversed end-diastolic velocity 1, 3

FGR with Absent End-Diastolic Velocity (AEDV)

• Deliver at 33-34 weeks of gestation 1, 2, 3
• At this gestational age, neonatal morbidity/mortality rates with AEDV exceed complications of prematurity 3
• If already beyond 34 weeks, delivery should not be delayed 2

FGR with Reversed End-Diastolic Velocity (REDV)

• Deliver at 30-32 weeks of gestation 1, 3
• REDV represents severe placental dysfunction with high risk of fetal demise 3

Mode of Delivery

Cesarean Section Indications

• Strongly consider cesarean delivery for FGR complicated by absent or reversed end-diastolic velocity 1, 2, 3
• Cesarean section is recommended for very preterm FGR or severe umbilical artery Doppler abnormalities 1
• FGR fetuses with abnormal Dopplers have 75-95% rates of intrapartum fetal heart rate decelerations requiring cesarean delivery 3
• Ominous cardiotocography pattern in the setting of FGR makes induction contraindicated; proceed directly to cesarean section 3

Vaginal Delivery Considerations

• If umbilical artery end-diastolic flow is present (not absent/reversed), induction of labor with continuous cardiotocography is recommended 1
• FGR alone is not an indication for cesarean section when Doppler is normal 1
• Continuous fetal heart rate monitoring during labor is mandatory 1

Pre-Delivery Interventions

Antenatal Corticosteroids

• Administer if delivery anticipated before 33 6/7 weeks 1, 3
• Also administer between 34 0/7 and 36 6/7 weeks in women at risk of delivery within 7 days who have not received a prior course 1, 3
• Should be given up to 34+0 weeks in most guidelines, though UK guidelines extend to 35+6 weeks 1

Magnesium Sulfate for Neuroprotection

• Administer for pregnancies <32 weeks of gestation 1, 3
• This is for fetal and neonatal neuroprotection 1, 3

Neonatal Coordination

• Coordination with neonatology is crucial for optimal resuscitation planning 2
• Prepare for potential complications including respiratory distress syndrome, necrotizing enterocolitis, and intraventricular hemorrhage 2

Common Pitfalls and Caveats

• Do not use biophysical profile as the only form of surveillance 1; however, it can be valuable when integrated with Doppler and cardiotocography, particularly when heart rate is non-reactive 4
• Do not rely on ductus venosus, middle cerebral artery, or uterine artery Doppler for routine clinical management of FGR 1, 3
• Cardiotocography alone is insufficient for surveillance; must be combined with umbilical artery Doppler 1
• An abnormal biophysical profile score in 8-27% of growth-restricted fetuses with non-reactive heart rate identifies need for delivery not suspected by Doppler findings alone 4
• Augmentation of labor is dangerous when contractions are already adequate and fetus shows severe compromise, as increasing uterine activity worsens placental perfusion 3