What are the FIGO (International Federation of Gynecology and Obstetrics) guidelines for the timing of delivery in a pregnant individual with Fetal Growth Restriction (FGR)?

FIGO Guidelines on Timing of Delivery in Fetal Growth Restriction

Note: The evidence provided does not contain specific FIGO (International Federation of Gynecology and Obstetrics) guidelines. The following recommendations are based on the most recent and highest quality guidelines available, primarily from the Society for Maternal-Fetal Medicine (SMFM) and the American College of Obstetricians and Gynecologists (ACOG), which represent the current standard of care for FGR management.

Delivery Timing Based on Doppler Findings

The timing of delivery in FGR is determined by umbilical artery Doppler findings and severity of growth restriction, with delivery ranging from 30-32 weeks for reversed end-diastolic velocity to 38-39 weeks for normal Doppler with mild FGR. 1

Normal Umbilical Artery Doppler

• Deliver at 38-39 weeks of gestation when estimated fetal weight (EFW) is between the 3rd and 10th percentile with normal umbilical artery Doppler 2, 1
• This recommendation balances the risk of stillbirth against complications of earlier delivery 3

Decreased Diastolic Flow (Elevated Resistance)

• Deliver at 37 weeks of gestation when umbilical artery Doppler shows decreased diastolic flow (S/D ratio, resistance index, or pulsatility index greater than 95th percentile) but without absent or reversed end-diastolic velocity 2, 1
• Also deliver at 37 weeks for severe FGR with EFW less than the 3rd percentile, regardless of Doppler findings 2, 4
• A large US cohort study demonstrated that delivery at 37 weeks reduces stillbirth rates in the presence of FGR risk factors 2

Absent End-Diastolic Velocity (AEDV)

• Deliver at 33-34 weeks of gestation for pregnancies with FGR and AEDV 2, 1, 4
• At this gestational age, neonatal morbidity and mortality rates associated with AEDV are higher than complications of prematurity 2
• AEDV indicates severe placental insufficiency with obliteration of approximately 70% of placental tertiary villi arteries 5

Reversed End-Diastolic Velocity (REDV)

• Deliver at 30-32 weeks of gestation for pregnancies with FGR and REDV 2, 1, 4
• Neonatal morbidity and mortality rates with REDV exceed complications of prematurity at this gestational age 2
• REDV represents severe placental dysfunction with extremely high risk of fetal demise 1

Surveillance Protocol Before Delivery

Frequency of Doppler Assessment

• Every 2 weeks for FGR with normal umbilical artery Doppler 1
• Weekly for decreased end-diastolic velocity or severe FGR (EFW <3rd percentile) 1, 4
• 2-3 times per week for absent end-diastolic velocity 1, 4
• Daily with hospitalization for reversed end-diastolic velocity 1, 4

Cardiotocography Monitoring

• Weekly cardiotocography after viability for FGR without absent or reversed end-diastolic flow 4
• Increase frequency to 1-2 times daily when FGR is complicated by absent or reversed end-diastolic flow 1, 4
• Critical caveat: Normal fetal heart rate testing does not exclude FGR and should never be used as the sole surveillance method, as heart rate changes occur late in the deterioration sequence 4

Periviable Period Management

Delivery Thresholds at Limits of Viability

• Thresholds of 26 weeks gestation or 500g have been suggested for delivery of pregnancies with severe early-onset FGR 2
• Neonatal survival increases from 13% at 24 weeks to 43% at 25 weeks and 58-76% at 26 weeks 2, 1
• Intact survival is 0% at 24 weeks, 13% at 25 weeks, and 6-31% at 26 weeks 2
• Coordination of care between maternal-fetal medicine and neonatology services is mandatory for delivery before 26 weeks or at 500g, with comprehensive patient counseling on neonatal morbidity and mortality 2, 1

Interventions Prior to Delivery

Antenatal Corticosteroids

• Administer if delivery is anticipated before 33 6/7 weeks of gestation 1, 4
• Also administer between 34 0/7 and 36 6/7 weeks in women at risk of delivery within 7 days 1, 4

Magnesium Sulfate for Neuroprotection

• Administer for pregnancies less than 32 weeks gestation for fetal and neonatal neuroprotection 1, 4

Mode of Delivery Considerations

Cesarean Delivery Indications

• Cesarean delivery should be strongly considered for pregnancies with FGR complicated by absent or reversed end-diastolic velocity based on the complete clinical scenario 1, 5
• Growth-restricted fetuses with AEDV/REDV are at increased risk for intrapartum fetal heart rate decelerations, emergency cesarean delivery, and metabolic acidemia 2, 1
• Studies report rates of intrapartum fetal heart rate decelerations requiring cesarean delivery in 75-95% of pregnancies with FGR and AEDV/REDV 2, 4

Vaginal Delivery Considerations

• If vaginal delivery is attempted, continuous electronic fetal monitoring is mandatory during labor 4
• Regional anesthesia is preferred for both trials of vaginal delivery and planned cesareans 6

Critical Pitfalls to Avoid

• Do not rely on ductus venosus, middle cerebral artery, or uterine artery Doppler for routine clinical management of FGR, as these are not recommended by ACOG 1
• Do not use biophysical profile or cardiotocography alone for surveillance 1
• Do not delay delivery beyond recommended gestational ages based on reassuring fetal heart rate patterns, as heart rate abnormalities appear late in the deterioration sequence 4
• Fetal growth evaluation should be performed at intervals of no less than 2 weeks, with 3-4 week intervals being more reliable due to inherent error in fetal biometry 4