Olsen 2010 growth calculator for preterm infants
Prepare postmenstrual age and measurement inputs for the Olsen 2010 preterm growth curves. This page checks the 23-to-41-week chart range and packages values for exact percentile and z-score calculation in PediTools or local chart software.
Last reviewed: 2026-04-28
Percentile handoff
What this page calculates
The calculator formats sex, postmenstrual age, and anthropometric measurements for the Olsen 2010 workflow. It flags whether the age falls inside the 23-to-41-week chart range before you use an official percentile engine.
- Use gestational or postmenstrual age at the measurement date, written as weeks plus days.
- Enter weight in grams, head circumference in centimeters, and length in centimeters.
- Use the copied entry package in PediTools or your EHR chart calculator for final percentile and z-score output.
When Olsen 2010 is useful
Olsen 2010 is often used for gestational-age-specific preterm size classification, including SGA, AGA, and LGA context in neonatal records. It is especially useful when a NICU or research dataset references the Olsen intrauterine curves rather than a Fenton chart.
Keep the chart family consistent when comparing serial values. A percentile from Olsen 2010 should not be trended interchangeably with a Fenton percentile unless the handoff note explains the chart change.
Official percentile tools
Preterm growth workflow
- Confirm gestational age at birth and age at the measurement.
- Repeat unexpected weight, length, or head circumference measurements.
- Calculate percentile and z-score in the official Olsen 2010 tool.
- Classify SGA, AGA, or LGA only using your local percentile cutoffs.
- Document the chart family before switching to Fenton, WHO, CDC, or local term charts.
Related calculators
References
FAQs
No. It prepares sex, postmenstrual age, weight, head circumference, and length for entry into PediTools or local software that calculates the Olsen 2010 percentile and z-score.
The Olsen 2010 intrauterine curves are commonly used for 23 through 41 completed weeks of gestational age. The PediTools implementation also treats gestational age by completed weeks.
Olsen 2010 is a U.S.-based intrauterine growth reference for preterm infants. Fenton charts are another preterm growth family and are often used for longitudinal postnatal transition through about 50 weeks postmenstrual age.
Do not extend Olsen 2010 beyond its chart range. For infants past the Olsen range, use corrected age with WHO, CDC, or local term infant growth chart guidance.
Document the chart source, completed gestational or postmenstrual age, sex, weight, length, head circumference, percentile or z-score, and whether the infant is SGA, AGA, or LGA by local policy.