Plotting Child Growth

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

  • Enter the child's weight and length/height as per Maternal and Child Health (MCH) practice guidelines.
  • Enter the date, weight and length/height in the child's health record.
  • Plot the child's weight and length/height on the relevant chart and compare to the previous measures.
    • Use dots to plot - don't join the dots into a line.
    • Age errors are the most common plotting mistakes.

Plotting new born and pre-term infants

For all infants born at 37 weeks and over, birth weight is plotted at age '0' on the growth chart.

A child born before 37 completed weeks gestation is considered preterm. See: Maternal and Child Health Service: Practice Guidelines 2009 (pdf - 791.74kb)

Growth of premature infants will be monitored by a paediatrician. After the infant has reached their expected birth date, growth is plotted on the WHO birth to two-year-old growth charts.

All lengths and weights for premature infants are plotted as 'corrected' age taking into account the number of weeks a baby was born early.

Corrected age = Gestational age - Number of weeks premature.

For example; Weight of a four month old (gestational age) ex-premature 32 weeks infant is plotted at two months on the chart (corrected age)

I.e. 4 months (gestational age) - 8 weeks (number of weeks premature) = 2 months (corrected age).

It is recommended to correct age for prematurity for children born before 37 weeks and until the age of two years. See: Maternal and Child Health Service: Practice Guidelines 2009(pdf - 791.74kb)

Key points about birthweight and early weight gain in infants

  • 80 per cent of babies lose some weight after birth.
  • Percentage birth weight rather than actual weight lost is more useful.
  • Less than 5 per cent of babies lose more than 10 per cent of birth weight.
  • If more than 10 per cent below birth weight at two weeks, the baby needs assessment for feeding problems or unrecognised illness.
  • Correct for prematurity until two years.

Activity D

Olivia was born at 32 weeks gestation and is now 10 weeks old. She has been home from hospital for 10 days and today is her first visit to the MCH centre. Birth weight was 1400 g; length 41.5 cm. Her current weight is 3000 g; length 50 cm.

Corrected age = Gestational age - Number of weeks premature

2 weeks (corrected age) = 10 weeks (gestational age) - 8 weeks (premature)

Figure D.1 shows Olivia's weight plotted at two weeks (corrected age). This places her weight on the 5th centile.

Figure D.2 shows Olivia's length plotted at two weeks (corrected age). This places her length between the 5th - 10th centile.

At this stage there are no concerns about her growth, but continued monitoring is recommended as per MCH practice guidelines.

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

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

Plotting infants, toddlers and preschoolers

For healthy infants, and once feeding is established, weight, length and head circumference are measured according to the Maternal and Child Health Service: Practice Guidelines 2009 (pdf - 791.74kb)

  • If closer monitoring is required, babies can be weighed up to once a month (up to six months), once every two months (six to 12 months) and once per three months (over one year)
  • Weight gain usually 'tracks' within one centile space.
  • Acute illness causes weight loss and the weight centile will fall, but it should usually return to the 'normal' centile within two to three weeks.
  • Less than two per cent of infants will show a sustained drop through two or more centile spaces. These children require further assessment
  • Length measurements can show wide variation due to variation in the method used (length, or height/stature) and the cooperation levels of the toddler.
  • When a child is measured standing up, the spine is compressed a little, so the child may appear 'shorter' compared to recumbent length measure. This has implications for the 'crossover' from under two to over two-year growth charts.

Accuracy in plotting requires:

  • date of recorded measurements
  • use dots to plot - don't join the dots into a line
  • age errors are the most common plotting mistakes.

Activity E

Jeremy is two years old next week and his height is 88 cm.

Figure E.1 Jeremy's length is 89 cm and is plotted between the 50th and 75th centiles on the WHO chart.

Figure E.2 Jeremy's height (stature) is also measured and is 88 cm. Height (stature) is plotted on the CDC chart. His height is also between the 50th and 75th centile on the CDC chart.

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

Figure E.1 WHO birth to 24 months, length 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 E.2 CDC 2 to 18 years old, height for age, boy
Source: World Health Organisation Child Growth Standards