NICU · Birth Size Assessment
Olsen 2010 Intrauterine Growth Chart
Classify birth weight, length, and head circumference (SGA / AGA / LGA) using the exact published Olsen 2010 LMS reference — the contemporary US-population intrauterine growth standard, 23–41 weeks.
Patient
Gestational age at birth
Birth weight
Length (optional)
Head circumference (optional)
About Olsen 2010
Olsen et al. (2010) built sex-specific intrauterine growth curves from 391,681 US infants (248 hospitals, 33 states, Pediatrix Medical Group, 1998–2006), replacing the older Lubchenco curves. It is widely used in US NICUs to classify size at birth and is considered the standard for VLBW (<1,500 g) and ELBW (<1,000 g) infants.
Enter gestational age and at least birth weight to calculate percentiles.
Method: Percentiles use the exact published Box-Cox LMS parameters (L, M, S) per gestational week and sex — Z = ((value/M)^L − 1) / (L·S) — the same method as the original paper, not a normal-distribution approximation. LMS values are linearly interpolated between adjacent whole weeks for fractional gestational ages.
Compare with the Fenton growth chart calculator, the other preterm growth reference commonly used in NICUs.
Clinical decision support only. Based on Olsen IE, Groveman SA, Lawson ML, Clark RH, Zemel BS. "New intrauterine growth curves based on United States data." Pediatrics. 2010;125(2):e214–e224. LMS reference values sourced from the open-source peditools R package (MIT license), cross-checked against published worked examples. Valid for 23–41 weeks gestational age; the 3rd and 97th percentiles at 23 weeks should be interpreted cautiously (small original sample). Always confirm classification with clinical judgment. PediaSuite is not affiliated with the chart's authors.
Reviewed by C. A. Leyva, MD, neonatologist · Last reviewed September 2026
References
- Olsen IE, Groveman SA, Lawson ML, Clark RH, Zemel BS. New intrauterine growth curves based on United States data. Pediatrics. 2010;125(2):e214–e224. doi:10.1542/peds.2009-0913
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