SMFM Recommendation on Ductus Venosus A-Wave Reversal in FGR
The Society for Maternal-Fetal Medicine (SMFM) explicitly recommends against using ductus venosus Doppler assessment for routine clinical management of fetal growth restriction 1.
Key SMFM Position
The 2020 SMFM Consult Series #52 states clearly: "We suggest that Doppler assessment of the ductus venosus, middle cerebral artery, or uterine artery not be used for routine clinical management of early- or late-onset fetal growth restriction (GRADE 2B)" 1.
This represents a notable departure from other international guidelines (particularly ISUOG and FIGO), which incorporate ductus venosus assessment into their surveillance protocols 2.
What SMFM Actually Recommends Instead
SMFM bases its entire FGR surveillance and delivery timing algorithm on umbilical artery Doppler findings alone:
Surveillance Protocol:
- Serial umbilical artery Doppler once FGR is diagnosed 1
- Weekly umbilical artery Doppler when decreased end-diastolic velocity is present (flow ratios >95th percentile) 1
- 2-3 times per week Doppler when absent end-diastolic velocity (AEDV) is detected 1
Delivery Timing Based on Umbilical Artery Findings:
- 30-32 weeks: FGR with reversed end-diastolic velocity (REDV) 1
- 33-34 weeks: FGR with absent end-diastolic velocity (AEDV) 1
- 37 weeks: FGR with decreased diastolic flow (but not absent/reversed) 1
The Practical Implication
If you observe ductus venosus a-wave reversal in an FGR case, SMFM guidance directs you to focus on the umbilical artery Doppler pattern to determine management, not the ductus venosus finding itself. The delivery timing algorithm is entirely umbilical-artery-based.
However, when REDV is present in the umbilical artery, SMFM does recommend:
- Hospitalization 1
- Antenatal corticosteroids 1
- Heightened surveillance with cardiotocography at least 1-2 times daily 1
- Consideration of delivery depending on the entire clinical picture and additional fetal well-being evaluation 1
Important Caveats and Context
Why SMFM Takes This Position:
The GRADE 2B recommendation reflects moderate-quality evidence suggesting that adding ductus venosus surveillance does not improve perinatal outcomes beyond umbilical artery Doppler alone in routine practice 1. Recent data from resource-limited settings supports this, showing comparable perinatal outcomes with umbilical-artery-focused surveillance versus multimodal protocols 3.
The Controversy:
This is genuinely controversial. Other major guidelines (ISUOG, FIGO) do recommend ductus venosus assessment, particularly in early-onset FGR with abnormal umbilical artery Doppler 2, 4. The 2026 consensus review notes that ductus venosus plays a central role in risk stratification in most international protocols—except SMFM 2.
When Ductus Venosus Might Still Matter Clinically:
Even though SMFM doesn't recommend routine use, emerging evidence suggests ductus venosus abnormalities may identify more severe hemodynamic compromise 5. In early-onset FGR with umbilical artery AEDV or REDV, some experts advocate for ductus venosus assessment to refine delivery timing in the 30-34 week window 4.
Practical Algorithm Following SMFM Guidelines:
If you detect FGR with any Doppler abnormality (including incidental ductus venosus a-wave reversal):
- Classify by umbilical artery Doppler pattern (normal, decreased, absent, or reversed end-diastolic velocity)
- Determine delivery timing based solely on umbilical artery findings using the thresholds above
- If REDV present: hospitalize, give steroids (if <34 weeks), increase cardiotocography to 1-2x daily, and strongly consider delivery at 30-32 weeks 1
- If <32 weeks at anticipated delivery: add magnesium sulfate for neuroprotection 1
- Consider cesarean delivery based on the entire clinical scenario when AEDV or REDV is present 1
The ductus venosus finding itself does not change the SMFM-based management algorithm—you follow the umbilical artery Doppler pattern.