Fetal Growth Calculator 2025: EFW, Percentiles, and Ultrasound Guide
Fetal growth monitoring detects IUGR, macrosomia, and anomalies. Our calculator uses Hadlock for EFW and INTERGROWTH-21st for percentiles. Enter BPD, HC, AC, FL from your scan.
Key Measurements
| Parameter | Measures | Normal Range |
|---|---|---|
| BPD | Head width | ±2 weeks |
| HC | Head size | Micro/macrocephaly |
| AC | Abdomen | Nutrition, liver |
| FL | Thigh bone | Skeletal dysplasia |
Hadlock EFW Formula
log₁₀(EFW) = 1.3596 + 0.0064(HC) + 0.0424(AC) + 0.174(FL) − 0.00386(AC×FL)
Percentile Interpretation
- <3rd: SGA — investigate
- 3rd–10th: Monitor growth
- 10th–90th: Normal
- 90th–97th: LGA risk
- >97th: Macrosomia
Step-by-Step Example
28 weeks: BPD 70mm, HC 260mm, AC 240mm, FL 50mm
- EFW = 1150g
- AC 45th, HC 50th, FL 52nd
- Normal symmetric growth
Red Flags
- AC lagging (IUGR)
- HC small (microcephaly)
- EFW <10th + Doppler abnormal
- EFW >90th + polyhydramnios
Scan Schedule
- 18–22 weeks: Anatomy
- 28–32 weeks: Growth
- 36 weeks: Position, fluid
- High-risk: Every 2–4 weeks
Multiples Adjustment
- Twins: 10–15% smaller
- Use twin-specific charts
- Discordance >20% → TTTS risk
Advanced Tips
- Pair with AFI
- Track kick counts
- Use GDM risk for macrosomia
FAQs
EFW accurate? ±15%. Serial better than single.
3D ultrasound better? No — 2D sufficient.
Low AC only? Check Doppler, placenta.
Conclusion
Regular fetal growth scans ensure healthy development. Use our 2025 calculator to interpret ultrasound. Always discuss with MFM specialist.
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