New Ballard Score (Gestational Age) — free guideline decision tool
Estimate neonatal gestational age with the New Ballard Score.
Open guideline tool →Guideline-based
Implements the decision logic from published clinical guidelines.
Runs in your browser
No installation. Enter the patient's values and get a guideline recommendation instantly.
Data stays local
Nothing is uploaded. Results are for licensed clinicians only.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Neuromuscular maturity subtotal (6 items: posture, square window, arm recoil, popliteal angle, scarf sign, heel-to-ear) | 12 points |
|---|---|
| Physical maturity subtotal (6 items: skin, lanugo, plantar surface, breast, eye/ear, genitals) | 13 points |
→Estimated gestational age34 weeks
- Total：Neuromuscular 12 + physical 13 = 25 → GA = 24 + 0.4 × 25 = 34 weeks (Late preterm)
- Conversion：GA (weeks) = 24 + 0.4 × total; total −10 to 50 maps to ~ 20–44 weeks; +5 points ≈ +2 weeks
- Accuracy：± 2 weeks; most accurate at 12–48 h of life (< 12 h better for the extremely preterm). May overestimate in small-for-gestational-age infants; cross-check with prenatal ultrasound/LMP
Common questions
What is New Ballard Score (Gestational Age)?
Estimate neonatal gestational age with the New Ballard Score.
How is New Ballard Score (Gestational Age) calculated? What is the core formula?
GA (weeks) = 24 + 0.4 × total of neuromuscular (6 items) and physical (6 items) maturity subtotals; total −10 to 50 maps to ~ 20–44 weeks.
When is New Ballard Score (Gestational Age) used?
Assign gestational age when dating is unknown or discordant with the exam.
What are the key clinical points for New Ballard Score (Gestational Age)?
Accuracy ± 2 weeks; most accurate at 12–48 h of life. May overestimate in small-for-gestational-age infants. Cross-check with prenatal ultrasound/LMP.
What are the limits and cautions when using New Ballard Score (Gestational Age)?
For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
How is New Ballard Score (Gestational Age) calculated in practice? Can you show a worked example?
Inputs: Neuromuscular maturity subtotal (6 items: posture, square window, arm recoil, popliteal angle, scarf sign, heel-to-ear) 12 points, Physical maturity subtotal (6 items: skin, lanugo, plantar surface, breast, eye/ear, genitals) 13 points → Result: Estimated gestational age 34 weeks（Total: Neuromuscular 12 + physical 13 = 25 → GA = 24 + 0.4 × 25 = 34 weeks (Late preterm), Conversion: GA (weeks) = 24 + 0.4 × total; total −10 to 50 maps to ~ 20–44 weeks; +5 points ≈ +2 weeks, Accuracy: ± 2 weeks; most accurate at 12–48 h of life (< 12 h better for the extremely preterm). May overestimate in small-for-gestational-age infants; cross-check with prenatal ultrasound/LMP）
Run New Ballard Score (Gestational Age) now
Estimate neonatal gestational age with the New Ballard Score.
Open guideline tool →For licensed clinicians. Not a substitute for clinical judgement.
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