A–Z Glossary

Z-score

A z-score indicates how far a baby's measurement differs from the average measurement in a standardized reference population.

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Typical baby size ranges

Typical baby size ranges

What “typical baby size” means “Typical” does not mean average, and average does not mean optimal for every infant. In clinical practice, baby size is described using anthropometric measurements: body weight, recumbent length, and head circumference. These values are plotted on age- and sex-specific growth charts, commonly using the World Health Organization (WHO) Child Growth […]

Weight-for-Length Percentiles Explained

Weight-for-Length Percentiles Explained

What Weight-for-Length Measures Weight-for-length is a proportional growth indicator. It plots a baby’s body weight against their recumbent length, which is the length measured while lying down. The measurement is particularly useful during infancy because standing height cannot yet be obtained reliably and because weight alone does not show whether body mass is proportionate to […]

Is my baby too small for age

Is my baby too small for age

What does too small for age mean? There is no single measurement that defines whether a baby is too small. Clinicians compare a baby’s weight, length, and head circumference with standardized reference data for babies of the same sex and age. The result is commonly expressed as a percentile or a z-score. A percentile describes […]