Fetal Growth Restriction Evaluation BETA
Interactive decision support for singleton fetal growth restriction and twin growth disorders, including monochorionic diamniotic selective fetal growth restriction. The tool emphasizes fetal size thresholds, umbilical artery Doppler, gestational age, additional risk factors, and the distinct management issues seen in MCDA twins.
Singleton FGR
MCDA selective FGR
Umbilical artery Doppler
Visible algorithm
Management guidance
6-question quiz
This page is educational decision support only. Delivery timing, surveillance intensity, and fetal therapy decisions must be individualized to the complete maternal-fetal picture and local expertise.
Wizard Inputs
Use this only for monochorionic diamniotic twins with suspected selective growth restriction.
Interpretation
Ready to calculate
Enter the pregnancy type, growth category, Doppler pattern, gestational age, and high-risk features. The page will rank the most relevant pathway and summarize likely management considerations.
Visible Clinical Algorithm: FGR Evaluation
Start here
First define the pregnancy type, the growth abnormality, and the umbilical artery Doppler pattern. Singleton FGR and MCDA selective FGR share some Doppler principles but have different surveillance and management considerations.
Step 1. Confirm the growth issue
Singleton
Think FGR when EFW or AC is below the 10th percentile.
Severe singleton FGR
EFW below the 3rd percentile is a higher-risk category even with a noncritical UA Doppler.
Twins
Consider discordance, smaller-twin growth percentile, chorionicity, and Doppler pattern.
Step 2. Use the umbilical artery Doppler
Normal UA Doppler
Usually lower risk than AEDV/REDV, but still requires surveillance.
AEDV / REDV
Escalates surveillance and usually changes timing of delivery in singleton FGR.
MCDA intermittent AREDF
Raises concern for Type III selective FGR in monochorionic twins.
Step 3. Apply the correct pathway
Singleton + normal UA + 3rd–10th percentile
Ongoing surveillance with later delivery if otherwise uncomplicated.
Singleton + AEDV / REDV
Closer surveillance, steroids when indicated, and earlier delivery planning.
MCDA selective FGR Type I / II / III
Requires monochorionic-twin-specific surveillance and referral logic.
Teaching Module
1. Key definitions +
- Singleton FGR: ultrasonographic estimated fetal weight or abdominal circumference below the 10th percentile.
- Severe singleton FGR: EFW below the 3rd percentile.
- MCDA selective FGR: monochorionic diamniotic twins with one smaller twin and a characteristic umbilical artery Doppler pattern in the smaller twin.
In monochorionic twins, chorionicity matters because placental vascular anastomoses make selective FGR biologically and clinically different from simple discordant growth in dichorionic twins.
2. Singleton FGR Doppler-based framing +
| Pattern | General meaning | Typical implication |
|---|---|---|
| Normal UA Doppler | Placental resistance not critically abnormal | Continued surveillance; delivery often later if otherwise stable |
| Decreased diastolic flow / elevated resistance | Placental insufficiency more likely | Closer surveillance and earlier delivery than uncomplicated mild FGR |
| AEDV | Higher-risk placental disease | Intensified surveillance and delivery generally around 33–34 weeks |
| REDV | Very high-risk placental disease | Hospital-level surveillance and delivery generally around 30–32 weeks |
3. MCDA selective FGR types +
| Type | Smaller twin UA Doppler | Teaching pearl |
|---|---|---|
| Type I | Positive end-diastolic flow | Usually the most stable pattern, but still requires monochorionic surveillance |
| Type II | Persistent absent or reversed EDF | Higher risk of fetal deterioration and very preterm delivery |
| Type III | Intermittent / cyclical AREDF | Unpredictable course; often considered particularly high risk |
In MCDA twins, concern for TTTS/TAPS, ductus venosus change, or major interval deterioration should prompt tertiary fetal medicine review.
4. Additional workup issues +
- Very early or unexplained singleton FGR increases concern for structural, genetic, infectious, or placental causes.
- SMFM recommends a detailed anatomy ultrasound for early-onset FGR and supports diagnostic testing with chromosomal microarray in selected cases.
- If invasive testing is chosen for unexplained early FGR, CMV PCR is recommended; routine toxoplasmosis/rubella/herpes testing is not recommended without other indications.
Management by Category
Singleton FGR with normal UA Doppler
- Continue serial growth and umbilical artery Doppler surveillance.
- When EFW is between the 3rd and 10th percentile and UA Doppler is normal, delivery is generally around 38–39 weeks if otherwise uncomplicated.
- Abnormal antenatal testing, oligohydramnios, maternal disease, or interval deterioration can change this plan.
Singleton FGR with abnormal UA Doppler, AEDV, or REDV
- Decreased diastolic flow or severe FGR often shifts delivery toward 37 weeks.
- AEDV usually shifts delivery toward 33–34 weeks.
- REDV usually shifts delivery toward 30–32 weeks with more intensive surveillance and hospitalization-level care depending on the full clinical picture.
Early-onset or unexplained singleton FGR
- Perform a detailed anatomy evaluation.
- Consider diagnostic testing, including chromosomal microarray, in selected cases.
- If invasive testing is chosen in unexplained early FGR, CMV PCR is recommended.
MCDA selective FGR Type I
- Often the most stable MCDA selective FGR pattern.
- Requires continued monochorionic surveillance with growth about every 2 weeks and Doppler at least weekly.
- Remain alert for conversion to a more unstable pattern or the emergence of TTTS/TAPS features.
MCDA selective FGR Type II or Type III
- Requires tertiary fetal medicine review.
- These patterns carry higher risks of fetal deterioration, intrauterine death, neurologic injury, and very preterm delivery.
- Management may include close surveillance, fetoscopic laser in selected circumstances, or selective reduction depending on gestational age and the complete MCDA picture.