Growth Charts and Anthropometry

Growth assessment compares a child's measurements with age- and sex specific reference charts. Weight, length or height, and head circumference are plotted, and the position on the chart is expressed as a centile or a SD score.

Growth patterns show the child's health over time. A single measurement is less informative than serial measurements, and the pattern of growth matters more than the absolute value.

Usage. It is used in routine child health surveillance, in the assessment of faltering growth and short stature, and in obesity assessment.

Weight. Measured on calibrated scales, with the child unclothed or in minimal clothing.

Length and height. Length is measured recumbent in children under 2 years, and height is measured standing in older children.

Head circumference. Measured with a non-stretchable tape over the eyebrows and around the occiput, and recorded with the centile.

Body mass index. Calculated from weight and height, and interpreted against age- and sex specific charts.

Charts. International growth references are used for children under 5 years, and reference charts are used for older children. Corrected age is used for preterm infants until about 2 years of age.

Interpretation.

• Measurements under the 3rd centile or over the 97th centile are flagged for review.
• Crossing two major centile lines downward indicates faltering growth and requires investigation.
• Weight-for-length or weight-for-height reflects nutritional status, and head circumference is tracked over time.
• Mid-parental height gives an expected adult height range, against which the child's growth velocity is compared.

Causes of abnormal growth. Inadequate nutrition, malabsorption, chronic illness, endocrine disorders, genetic syndromes, and social factors.

Critical values and findings needing immediate action.

• Severe wasting or weight loss in a child with acute illness requires immediate medical review.
• Head circumference that is falling across centile lines requires urgent assessment.

Limitations and artefacts. Measurement error is common, particularly in length and height in young children. Clothing and wrong chart selection cause misinterpretation. A single measurement cannot establish a growth trend.

Follow up tests. Bone age X-ray, thyroid function tests, coeliac serology, and urine tests for renal disease where the pattern suggests a cause. Further assessment is directed by the growth pattern and the clinical findings.

Special groups. Preterm infants use corrected age. Children with genetic syndromes are assessed with syndrome specific charts where available. Adolescents require adult referenced interpretation as puberty approaches.