Late Pregnancy · Growth Restriction
FGR Composite Doppler
Composite Doppler assessment for fetal growth restriction (FGR). UA + MCA + CPR + DV + uterine artery. Early-onset (<32 wk) vs late-onset patterns differ. TRUFFLE-based delivery timing in extreme preterm.
Last reviewed 2 June 2026
FGR Doppler composite
Unified FGR severity and delivery-timing plan
Umbilical artery (UA)
Cerebroplacental ratio (CPR)
MCA peak systolic velocity (PSV)
Ductus venosus (DV) a-wave
Computerised CTG — short-term variation (STV)
Tier 0 — SGA / constitutionally small, no flow concerns
Tier 0 / 5
Surveillance every 2–3 weeks. Aim delivery 38–39 wk if SGA without abnormal Doppler (ACOG 234). No early intervention indicated; over-intervention worsens outcomes in this group.
Troubleshooting + common pitfalls
- Confusing SGA with FGR. ~70 % of fetuses with EFW < 10th centile are constitutionally small with normal Dopplers — these do not need early delivery. The Delphi consensus (Gordijn 2016) requires either < 3rd centile alone, OR < 10th centile PLUS one Doppler abnormality.
- MCA-PSV high without anaemia context. ≥ 1.5 MoM screens for fetal anaemia (Rh / parvovirus / TAPS), not FGR severity per se — investigate the cause. Don’t confuse with brain-sparing CPR.
- Bandwidth issues with CPR alone. CPR is most useful in late-onset FGR (> 32 wk) where AEDF/REDF are uncommon. In early-onset, DV is the more reliable longitudinal marker (TRUFFLE).
- Doppler “snapshots” vs trends. Single abnormal values can be transient. Repeat within 24 h before escalating delivery timing unless ≥ Tier 4.
- Steroid completion vs deteriorating DV. If DV becomes reversed mid-course, deliver — partial steroid coverage beats lost fetus. ANS effect rises sharply at 24 h but a single dose still helps.
- Maternal indications override. Pre-eclampsia, abruption, or ROM trigger delivery regardless of where the fetus sits on the FGR curve.
- Late-onset FGR > 36 wk. CPR < 5th alone justifies delivery at 37 wk even if UA Doppler is normal (Figueras 2014).
- Twin pregnancies. Discordance ≥ 25 % with Doppler abnormality in one twin — manage as FGR; consider TTTS / sFGR specifically in monochorionic twins.
Educational tool only — not medical advice. ACOG PB 234 (2021); ISUOG 2021; TRUFFLE Lancet 2015; SMFM Consult #52. Decisions made by maternal-fetal medicine team with sequential Doppler trends and the full clinical picture.
What does this mean?
The most consequential thing this tool does is collapse five Doppler / biophysical inputs into one tier tied to a delivery-timing decision. Without this synthesis, individual abnormalities tempt either premature intervention (delivering for an isolated CPR drop) or dangerous delay (continuing surveillance with reversed DV). The TRUFFLE trial (Lancet 2015) defined the modern early-onset surveillance pathway and proved that DV-guided delivery improved 2-year neurodevelopmental survival versus cCTG- or weekly-CTG-led approaches. For late-onset FGR (> 32 wk) the natural history is different — AEDF/REDF are uncommon, and decisions rely more heavily on CPR + EFW trajectory + maternal indication. The composite tier here makes the “ought we deliver now?” question explicit: Tier 0 = wait for term, Tier 5 = deliver now after steroids. Two errors to avoid: confusing constitutionally small (Tier 0) with FGR — ~70 % of EFW < 10th centile fetuses are simply small, and over-intervention worsens outcomes; and confusing transient single abnormal Dopplers with sustained trends — repeat within 24 h before escalating unless you’re already at ≥ Tier 4.
What is FGR?
Baby not growing to potential due to placental issue. Not same as SGA (small but maybe healthy).
DELPHI 2016 criteria:
- EFW <3rd centile alone, OR
- EFW <10th centile + abnormal Dopplers OR abnormal growth velocity OR low amniotic fluid.
Early vs late-onset
- Early-onset (<32 wk): severe placental disease; UA abnormalities prominent; brain-sparing + DV abnormalities sequential; outcomes generally worse.
- Late-onset (≥32 wk): milder placental dysfunction; UA often normal; CPR drops (best detection); outcomes generally better.
Doppler components
- UA: placental resistance; AEDF/REDF progressive.
- MCA: brain perfusion; low PI = brain-sparing.
- CPR: MCA-PI ÷ UA-PI; sensitive for late-onset.
- DV: cardiac/circulatory compromise marker.
- Uterine artery: maternal side; high resistance + notching = PE/IUGR risk.
Delivery timing
- Early-onset: TRUFFLE-based DV decision.
- 30+ wk + REDF: deliver 32 wk after steroids.
- DV abnormalities: deliver soon.
- Late-onset + abnormal CPR at term: deliver 37-38 wk.
- Static growth over 2 weeks: deliver.
TRUFFLE trial
Early-onset FGR + AEDF randomised to delivery timing by cCTG, DV early, or DV late changes. DV-late group: best 2-year neurodevelopmental outcomes. Informs current UK / European practice.
Causes
- Placental insufficiency (commonest).
- Maternal: smoking, alcohol, drugs, chronic disease.
- Fetal: chromosomal anomalies, congenital infection.
- Multiple pregnancy.
- Idiopathic.
Prevention measures
- Stop smoking.
- Healthy weight + diet.
- Aspirin from <16 wk if PE risk factors.
- Address chronic conditions.
- Avoid alcohol/drugs.
- Routine antenatal care + serial measurements.
- Growth scans if at risk.
NICU expectations
- Small baby support.
- Respiratory help.
- NG feeding initially.
- Hypoglycaemia + thermal regulation.
- Hyperbilirubinaemia monitoring.
Recurrence in future pregnancies
- PE-related FGR: ~25-50%.
- APS: aspirin + LMWH.
- Idiopathic: 20-30%.
- Preconception care + early surveillance.
Different scenarios
Scenario 1: 28 wk, EFW 4th centile, UA PI raised but positive flow
Increase scan frequency. Aspirin if PE workup. Plan delivery 36-37 wk if stable.
Scenario 2: 30 wk severe early-onset FGR + AEDF
Admit. Steroids. Daily Dopplers + DV monitoring. Deliver via TRUFFLE protocol.
Scenario 3: 36 wk late-onset, EFW 8th centile, low CPR
Deliver 37 wk by induction or C-section.
Scenario 4: Static growth at 32 wk over 2 weeks
Steroids if needed. Consider delivery within 24-48h.
Scenario 5: Twins with sFGR, one growing poorly
Specialist fetal medicine. Doppler-staged sFGR (Types I, II, III). Delivery timing complex.
Care guidance — FGR
- Combined Doppler scan most informative.
- Serial monitoring of trajectory.
- Steroids if preterm anticipated.
- Magnesium <32 wk.
- NICU prep in advance.
- Long-term developmental follow-up.
- Preconception planning for next pregnancy.
- Mental health support — anxiety high.
Sources
- Lees CC, et al. TRUFFLE: 2 year neurodevelopmental and intermediate perinatal outcomes in infants with very preterm fetal growth restriction. Lancet 2015.
- Gordijn SJ, et al. Consensus definition of fetal growth restriction: a Delphi procedure. UOG 2016.
- RCOG Green-top Guideline 31. SGA management.
- NICE NG137. Twin and triplet pregnancy.
Recommended for this calculator
Frequently asked questions
What is fetal growth restriction (FGR)?
Baby NOT growing to potential due to placental issue. NOT same as SGA (small for gestational age — small but maybe constitutionally small + healthy). FGR = pathological smallness. CRITERIA (DELPHI 2016 consensus): EFW <3rd centile alone; OR EFW <10th centile + abnormal Dopplers OR abnormal growth velocity OR low amniotic fluid; OR ABDOMINAL CIRCUMFERENCE <3rd or with abnormal Dopplers. EARLY-ONSET (<32 wk): placental severe disease, often progressive. LATE-ONSET (≥32 wk): more common; subtle; minimal UA changes; CPR drops.
What do all the Doppler tests measure?
Comprehensive fetal monitoring: (1) UMBILICAL ARTERY (UA) — placental resistance; AEDF/REDF progressive abnormality; (2) MIDDLE CEREBRAL ARTERY (MCA) — brain perfusion; low PI = brain-sparing; (3) CPR (cerebroplacental ratio) — sensitive for late-onset FGR; (4) DUCTUS VENOSUS (DV) — cardiac/circulatory compromise marker; A-wave changes indicate decompensation; (5) UTERINE ARTERY — maternal side; high resistance + notching = PE/IUGR risk; (6) AORTIC ISTHMUS — sometimes used. COMBINED Doppler = COMPOSITE picture.
What's the difference between early-onset and late-onset FGR?
EARLY-ONSET (<32 wk): (1) SEVERE placental disease; (2) UA abnormalities prominent (AEDF, REDF, REDF); (3) BRAIN-SPARING + DV abnormalities sequential; (4) DELIVERY balanced against extreme preterm complications; (5) WORSE outcomes generally. LATE-ONSET (≥32 wk): (1) MILDER placental dysfunction; (2) UA often normal; (3) CPR drops (best detection); (4) BRAIN-SPARING subtle; (5) DV usually normal; (6) DELIVERY usually possible at near-term gestation; (7) OUTCOMES generally better.
How is delivery timing decided?
Based on Doppler trajectory + EFW + maternal factors. EARLY-ONSET: TRUFFLE study + protocols guide DV-based decisions. AT 30+ WK with REDF: deliver 32 wk after steroids. WITH DV abnormalities (a-wave): deliver immediately or soon. LATE-ONSET: at term with abnormal CPR — deliver 37-38 wk. WITH GROWTH STATIC over 2 weeks: deliver. NO ONE THRESHOLD — composite picture + shared decision-making with parents.
What's TRUFFLE?
TRUFFLE (Trial of Umbilical and Fetal Flow in Europe, Lees 2015 Lancet) randomised early-onset FGR (<32 wk, AEDF) to delivery timing based on: (1) cCTG (computerised CTG short-term variability), (2) DV early changes, (3) DV late changes. RESULTS: DV-LATE group had best 2-year neurodevelopmental outcomes. EXTENDED follow-up: subtle benefits. PROTOCOL: use DV waveform abnormality to decide delivery timing in very preterm FGR. INFORMED current UK / European practice.
What scans + tests do I need?
ROUTINE for high-risk FGR: (1) WEEKLY-MONTHLY scans depending on severity; (2) UMBILICAL ARTERY Doppler; (3) MCA + CPR; (4) AMNIOTIC FLUID; (5) ESTIMATED FETAL WEIGHT (growth velocity); (6) BIOPHYSICAL PROFILE in severe cases; (7) DV Doppler in severe early-onset; (8) CTG (NST) regularly; (9) MATERNAL BP/urine if PE concern; (10) BLOOD TESTS (PE / cholestasis screen). FREQUENCY scales with severity.
Will my baby be in NICU?
OFTEN YES. PRETERM delivery common (especially early-onset FGR). NICU NEEDS: small baby support; respiratory help; feeding support (NG tube initially); hypoglycaemia monitoring; thermal regulation (small babies lose heat); hyperbilirubinaemia. LATER-onset FGR near-term: may avoid NICU; postnatal care often adequate. NEONATAL team prepared in advance.
What's the cause?
(1) PLACENTAL INSUFFICIENCY (commonest): abnormal placental development; spiral artery problems; pre-eclampsia related; (2) MATERNAL FACTORS: smoking, alcohol, drugs; severe nutritional deficiency; chronic disease; (3) FETAL FACTORS: chromosomal anomalies; congenital infection (CMV, toxo, rubella, syphilis, parvovirus); structural anomalies; (4) MULTIPLE pregnancy; (5) IDIOPATHIC. WORKUP: detailed scan; infection screen; sometimes karyotype.
Can FGR be prevented?
(1) Stop SMOKING; (2) HEALTHY weight + diet; (3) ASPIRIN from <16 wk if PE risk factors; (4) ADDRESS chronic conditions (HTN, diabetes, kidney); (5) AVOID alcohol/drugs; (6) AVOID known infections; (7) ROUTINE antenatal care + serial measurements (fundal height); (8) GROWTH SCANS if at risk. NOT all FGR preventable; sometimes biological factors.
Will my baby have lasting effects?
VARIES. FACTORS: severity; gestational age at delivery; underlying cause; postnatal care. POTENTIAL effects: (1) NEURODEVELOPMENTAL — slight increased risk especially early-onset; (2) ADULT cardiovascular + metabolic disease (DOHaD — Developmental Origins of Health and Disease); (3) GROWTH catch-up — most by age 2-3; some persist; (4) LEARNING + behavioural — mild differences possible. MAJORITY of FGR babies develop normally with appropriate care + supportive environment.
What about the placenta after birth?
EXAMINED histologically in cases of severe FGR / stillbirth / suspected placental disease. FINDINGS may inform: future pregnancy planning; recurrence risk; underlying maternal vascular pathology; rare placental tumours. RESULTS take weeks. SHARED with parents at follow-up appointment. INFORMS counselling for next pregnancy.
What about my future pregnancies?
RECURRENCE varies by cause: (1) PE-RELATED FGR: ~25-50% recurrence; aspirin from <16 wk reduces; (2) ANTIPHOSPHOLIPID SYNDROME: aspirin + LMWH from positive test; (3) UNDERLYING maternal disease: optimise pre-pregnancy; (4) IDIOPATHIC: 20-30% recurrence; preconception care + early surveillance. PRECONCEPTION CONSULTATION with maternal-fetal medicine specialist valuable. SUBSEQUENT pregnancy: serial growth scans + Dopplers.
What's the long-term follow-up?
(1) HOSPITAL discharge plan; (2) HEALTH VISITOR / GP regular checks; (3) DEVELOPMENTAL assessments at 3, 6, 12, 24 months + ongoing; (4) PHYSIO / OT / SALT if needed; (5) HEARING + VISION checks; (6) GROWTH monitoring with adjusted age (corrected age) if preterm; (7) CARDIOVASCULAR + metabolic check-ins as adult later in life. MANY FGR children completely catch up + thrive.
How does this relate to other calculators on BumpBites?
Companion: /calculators/cpr-doppler; /calculators/mca-psv; /calculators/ua-dv-doppler; /calculators/fetal-weight; /calculators/biophysical-profile; /calculators/aspirin-pe-prevention; /calculators/antenatal-steroids; /calculators/magnesium-sulphate; /calculators/cervical-length.