FGR + AEDV at 35 weeks

Clinical approach to late-preterm FGR with absent umbilical artery end-diastolic velocity (placental insufficiency phenotype).

Audience: OB residents / fellows / MFM

Scope: screening → diagnosis → management

Teaching point

At 35 weeks, persistent AEDV usually crosses the threshold for delivery planning now, not prolonged expectant management.

Why it matters

• High placental resistance → fetal hypoxemia risk
• Stillbirth risk rises as Dopplers worsen
• Labor tolerance may be limited

High-contrast, minimal text: designed for oral teaching. Use local protocols + individualized judgment.

Define the problem

Confirm you are managing FGR (not constitutionally small) plus pathologic placental Doppler.

Diagnosis frame

• EFW or AC <10th percentile (severe: <3rd)
• Umbilical artery: absent end-diastolic flow
• Exclude anomalies / infection when indicated

Common pitfalls

• Dating error → mislabeling FGR
• Single Doppler sample → repeat for persistence
• Mixing “SGA” with “FGR” in counseling

Point: get the phenotype right before acting. AEDV = placental insufficiency until proven otherwise.

Pathophysiology

AEDV reflects marked placental vascular resistance and reduced fetoplacental perfusion.

Concept chain

• Abnormal placentation → high resistance villous bed
• ↓ Diastolic flow → ↓ oxygen delivery reserve
• Progression risk: AEDV → REDV → acidemia

Clinical meaning

Not “small only.” It is a hemodynamic signal of compromised placental function.

Umbilical artery waveform (schematic)

Point: AEDV is a severity marker for placental insufficiency. Progression can be rapid or stepwise.

Risk factors to surface (fast)

Risk stratification helps anticipate maternal disease and neonatal course.

Maternal

• Chronic HTN / preeclampsia
• Renal / autoimmune disease
• Smoking, substance exposure

Placental / pregnancy

• Abnormal placentation
• Multiple gestation
• Prior FGR / stillbirth

Fetal

• Aneuploidy / anomalies
• Infection (when suspected)
• Severe oligohydramnios

Point: AEDV is often a placental disease signal; look for maternal hypertensive disease. Investigations should be indication-driven.

Immediate confirmation at 35 weeks

Before action: confirm persistence, fetal status, and competing indications for expedited delivery.

Do now

• Repeat UA Doppler (confirm persistent AEDV)
• BPP or NST + AFI/SDP
• Maternal evaluation: BP, symptoms, labs if indicated

Interpretation

• Nonreassuring testing → deliver urgently
• Reassuring testing still ≠ “safe for weeks”
• Document dating + growth trajectory

Uncertainty flag

Intermittent vs persistent AEDV may differ in risk; manage conservatively when uncertain.

Point: confirm phenotype, then move to delivery planning. Avoid serial delays waiting for “more data.”

Delivery timing: where 35 weeks fits

Evidence-based guidance generally recommends earlier delivery for AEDV than 35 weeks.

Guideline anchor (concept)

• AEDV typically triggers delivery around 33–34 weeks
• REDV earlier (often 30–32 weeks)
• At 35 weeks: balance shifts toward delivery now

Risk tradeoff at 35 weeks

• Placental failure risk persists (stillbirth/acidemia)
• Late-preterm neonatal risks are real but lower than earlier GA
• Goal: minimize exposure time to compromised placenta

Point: AEDV at 35 weeks is “past threshold” for expectant management. Source concepts: SMFM Consult #52; ACOG FGR PB.

Antenatal meds (late preterm)

Use interventions that improve neonatal outcomes without delaying indicated delivery.

Consider

• Betamethasone if delivery likely within 7 days and no prior course
• Group B strep prophylaxis per status
• NICU consult; plan thermoregulation/glucose support

Not routine at 35 weeks

• Magnesium neuroprotection (typically <32 weeks)
• Tocolysis to “finish steroids” in a compromised fetus
• Prolonged observation if testing deteriorates

Principle

Steroids may be helpful, but fetal status dictates urgency.

Point: optimize neonatal transition, don’t justify unsafe delay. Align with institutional late-preterm steroid criteria.

Mode of delivery: decision framework

AEDV increases risk of intrapartum compromise; route should be individualized.

Favors induction

• Reassuring testing; no additional red flags
• Favorable cervix; vertex; reasonable EFW
• Capacity for continuous EFM + rapid operative delivery

Favors cesarean

• Nonreassuring NST/BPP, recurrent decelerations
• Severe growth restriction + poor reserve
• Unfavorable cervix with high likelihood of prolonged labor

Communicate clearly

“Higher chance of urgent cesarean during labor” should be explicit in counseling.

Point: AEDV is not an automatic cesarean, but it lowers labor tolerance. Document shared decision-making.

If delivery is not immediate (rare)

Only if testing is reassuring and a brief, protocolized window is clinically justified.

Minimum surveillance

• Inpatient or very close monitoring
• Frequent NST/CTG; repeat UA Doppler
• Low threshold to deliver with any deterioration

Triggers to deliver now

• Reversed UA flow or worsening Dopplers
• Abnormal CTG / BPP, oligohydramnios worsening
• Maternal indication (preeclampsia, severe HTN)

Reality check

At 35 weeks with persistent AEDV, extended expectant management is usually not favored.

Point: surveillance cannot “treat” placental insufficiency. Use standardized pathways to reduce variability.

Intrapartum priorities

Assume limited reserve; plan for rapid response to evolving fetal acidemia.

Monitoring

• Continuous EFM; interpret conservatively
• Early attention to recurrent variable/late decels
• Prompt escalation: intrauterine resuscitation + decision

Operational readiness

• OR availability; anesthesia aware
• Neonatal team present at delivery
• Avoid prolonged second stage if tracing deteriorates

Key phrase

“Low threshold for operative delivery.”

Point: the safest plan is the one you can execute quickly. Debrief the team before starting induction.

Neonatal implications at 35 weeks

Counsel on both prematurity and growth restriction effects.

Expected issues

• Hypoglycemia risk; feeding support
• Thermoregulation challenges
• Respiratory morbidity possible (late preterm)

Delivery room plan

• NICU/SCN presence; glucose protocol
• Delayed cord clamping if stable and feasible
• Placenta to pathology (often high yield)

Point: anticipatory guidance reduces surprise and improves coordination. Align with institutional late-preterm care bundles.

One-slide algorithm (take-home)

For 35 weeks with persistent AEDV in FGR.

Algorithm

• Confirm dating + persistent AEDV
• Assess fetal status (NST/BPP + fluid)
• Plan delivery now (route individualized)
• Consider late-preterm steroids if feasible without unsafe delay

Evidence anchors

• SMFM Consult Series #52: FGR + Doppler-based timing
• ACOG Practice Bulletin: FGR evaluation and management
• Key idea: AEDV indicates high-risk placental insufficiency

This deck is educational; apply local protocols and patient-specific factors.

Point: at 35 weeks, AEDV usually means “deliver.” SMFM/ACOG-aligned principles.