6.3 Normal growth
Physical growth is measured by weight, length (height) and head circumference. Regular weighing is part of most Western well-baby care systems. Growth charts are used universally in pediatric care.1 Growth charts are used to plot the infant's data for comparison with expected growth in each of these parameters.
Growth charts plot a curve of the median, then plot the highest and lowest curves of normal growth on either side. The most common ones in use have percentile curves.
- The 3rd percentile reflects that 3% of children are either at or below this line.
- The 97th percentile indicates that 97% of children will be either at or below that line.
- The 50th percentile is the median and 50% of children will be either equal to or below this curve; likewise 50% of children will be either equal to or above this curve.

Look at the movie not the photo
Plotting of a child's data on one occasion in time has limited value. The important information is what happens to that child's data over time.
- is the child's data continuing to cross through curves, or
- is the child's data tracking normally along an upward curve, even if it is the 3rd percentile?
Weighing of babies is not an innocuous procedure
Researchers have found that clinic visits often focused around the weighing of the baby with little attention being given to discussing other child care matters.2 It was noted that the interpretation of an acceptable weight gain was reduced to the expectation that the plotted weight should mirror one of the curves on the growth chart.
Mothers in this study, and others, 3 were found to change their feeding practices at the expense of breastfeeding to increase weight gain to stay on or exceed a growth curve.
“ ... the routine of weighing risks becoming a ritual practice with potential to undermine infant nutrition rather than a supportive means to encourage the best care possible for individual babies.
” (p94) 2
Before weighing a baby:
- ask the mother if she has any concerns about her baby.
- discuss the baby's breastfeeding behavior and intake of complementary foods (if age appropriate)
- ask about the baby's output - urine and stooling.
- observe the achievement of age-appropriate developmental skills.
- observe the baby's general condition: skin turgor, color, adipose distribution (particularly as the mother takes the baby's clothes off in preparation for weighing).

Surprised?
Absolutely NOT!!!
The weight readout on the scale should not come as a surprise to you if you have had a good discussion with the mother about those factors before weighing baby.

Workbook Activity 6.4
Complete Activity 6.4 in your workbook.

Before weighing this exclusively breastfed Papua New Guinean baby would you anticipate having any concerns? If not, why not?
Photograph © D.Fisher, IBCLC
What influences movement through growth curves?
A variation from a growth curve is only one observation. Further history-taking, other observations, investigations or time may be required before a definitive explanation can be given.
Reasons data may fluctuate:
- Data is plotted on a growth chart based predominantly on artificially-fed children. (Ensure you are using the WHO growth charts) Artificially-fed babies have a markedly different, and therefore abnormal, growth trajectory.
- Child was born large, but is genetically determined to be slighter - or vice versa.
- Child has had a temporary illness, losing weight which will be quickly regained when healthy again.
- Inadequate nutritional sustenance to support growth; or excessive, but poor quality foods causing obesity.
- Chronic illness that prevents normal growth.
WHO Child Growth Standards
Print a copy of the percentile charts


Accurately weighing an infant
In comparing balance, spring and electronic scales most studies found greatest accuracy using electronic scales, with newer scales being more accurate than older scales. Scales should be regularly re-calibrated.
For greatest accuracy:
- weigh the infant on the same set of scales each time
- weighing procedure to be performed by the same person at each visit, using their usual technique
- weigh the baby at approximately the same time of day
- weigh the baby at the same time in relation to a feed, eg. straight after feeding
- weigh the baby naked. Weighing baby with a diaper/nappy or clothed results in larger discrepancies.
- take time to concentrate on accurately plotting the weight. One study4 found >28% of points were plotted inaccurately.
What should I remember?

- Normal infant growth occurs within a range.
- All infant measurements should be plotted using the WHO Child Growth Standards.
- Consider weight as one useful measurement of progress.
- The growth trajectory of the healthy breastfed infant is the norm for all infants.
- The important techniques which make weighing as accurate as possible.