Background
The World Health Organization (WHO) conducted a Multicentre Growth Reference Study (MGRS) from 1997 to 2003 to develop new growth charts for assessing the growth and development of infants and young children worldwide.
Primary data were collected from about 8,500 children from diverse ethnic and cultural settings (Brazil, United States, Ghana, India, Norway, Oman).
These charts describe expected physiological growth in children under five and establish breast‑fed infants as the normative model of growth and development.
Statistical reminders
- MoM (Multiple of the Median)
- Percentile
- Z score
These indicators convey two notions: the expected central value (median/mean) and the allowable dispersion around it.
Two WHO chart types
Percentile charts
Indicate the percentage of children with values below the measured one. Less suited for extremes and less convenient for precise calculations.
Example: the 97th percentile means 97% of the population has a lower value than the measurement.
Z‑score charts
Express deviation from the mean in standard deviations (SD). More precise and recommended by WHO.
Anthropometric measurements (reminders)
- Length/height‑for‑age
- Weight‑for‑age
- Weight‑for‑length/height
- BMI‑for‑age
- Head circumference‑for‑age (HC)
- Mid‑upper arm circumference‑for‑age (MUAC)
- HCSS‑for‑age
- TST‑for‑age
Z‑score charts (girls/boys)
Available for each measurement above and intended as a standardized international reference.
Interpretation grid
Shaded band: normal growth zone.
- A point exactly on +1 lies within the normal growth zone.
- A point on −1 also lies within the normal zone.
- A point on +2 is between +1 and +2.
- A point on +3 is between +2 and +3.
- A point on −2 is between −1 and −2.
- A point on −3 is between −2 and −3.
