Interpreting Child Growth

What is normal growth?

Weight and length/height 'tracking' along centile lines indicates normal growth.

  • Serial measurements are needed for growth assessment.
  • Growth assessment involves looking at the overall trajectory of weight and length.
  • Very few babies grow along the same centile line from birth.
  • Weight and length /height 'tracking' along centile lines indicates normal growth.
  • 93 per cent of all children grow within the centile range (5th - 98th centiles).
  • Despite many parents' perceptions the 50th centile is not the goal for each child.

What is poor growth?

  • Weight or length below the 5th centile.
  • Weight or length crossing centiles downwards.

What is excessive growth?

  • Weight or length above the 98th centile.
  • Weight or length crossing centiles upwards.
  • BMI above the 85th centile = overweight.
  • BMI above the 95th centile = obese.

Steps for effective growth assessment

  • Age-appropriate, gender-specific suitable growth chart.
  • Correct measurement technique and calibrated age-appropriate equipment.
  • Accurate transfer of measurements to chart or computer program.
  • Correct interpretation (understanding of normal and abnormal growth) and context of measurements (e.g. recent feed, nappy, clothing)
  • General assessment of child − are they otherwise happy, healthy.
  • Single versus serial measurement. Many children who are otherwise healthy have growth centiles at the extremes of the curves. Children who grow at the extremes of the growth curves but have normal growth rates are likely to be healthy. Conversely, growth rates that are persistently increasing or decreasing (crossing centiles) are not normal and need further investigation.
  • Time, expertise and resources to explain measurements to parents and/or demonstrate plotting in the child health record.
  • Sensitivity and a partnership approach − child nutrition and growth are highly emotive aspects of parenting and child health practitioners should avoid, at all costs, generating unnecessary anxiety about child growth.
  • Access to specialist advice and referral if necessary.

Keep watch

  • Weight or length/stature less than 5th centile.
  • Weight or length/stature greater than 98th centile.

Further investigate

  • Unexplained weight loss or weight not re-gained following acute illness.
  • Weight or length/stature 'plateau'.
  • Weight, length/stature or BMI increasing or decreasing centiles on growth chart.
  • BMI greater than 85th centile.

Activity F

Growth assessment depends on precise measurements and careful plotting and interpretation of these findings.

Figure F.1 shows the weight gain for a boy at the 5th centile on the CDC chart. His weights are: 2.6 kg at birth, 3.3 kg at one month, 4.3 kg at two months and 5.4 kg at four months.

Figure F.2 shows the same weights plotted on the WHO chart. On the WHO chart, the 5th centile weight at four months is approximately 5.8 kg. This drop below the 5th centile should prompt closer monitoring of weight. However, this example is also likely to be an aberration of the changeover of growth charts for a small number of children.

Figure F.1 and Figure F.2 - visual representation of the previous paragraphs 

Activity F.1 CDC birth to 36 months, weight for age, boy
Source: Developed by the National Center for Health Statistics in collaboration with the National Center for Chronic Disease Prevention and Health Promotion (2000).
Figure F.2 WHO birth to 24 months, weight for age, boy
Source: World Health Organisation Child Growth Standards

For further information, see: Interpreting Child Growth (pdf - 83.8kb)