Pediatric Nutrition in Practice

10 Puntis

able measurements (http://healthsciences.

qmuc.ac.uk/labweb/Equipment/skin_fold_

calipers.htm); take triceps skinfold thickness

readings at the mid upper arm using the re-

laxed non-dominant arm; the layer of skin and

subcutaneous tissue is pulled away from the

underlying muscle, and readings are taken to

0.5 mm, 3 s after the application of the calli-

pers; measurements can also be taken at oth -

er sites (www.cdc.gov/nchs/data/nnyfs/Body_

Measures.pdf)

Growth

Growth rate in infancy is a continuation of the
intrauterine growth curve, and is rapidly deceler-
ating up to 3 years of age. Growth in childhood is
along a steady and slowly decelerating growth
curve that continues until puberty, a phase of
growth lasting from adolescence onwards. Dur-
ing puberty, the major sex differences in height
are established, with a final height difference of
around 12.5 cm between males and females.
Growth charts are derived from measurements of
many different children at different ages (cross-
sectional data). Data on growth of children are
distributed ‘normally’ (i.e. they form a ‘bell-

shaped’ curve). These data can be expressed

mathematically as mean and SD from the mean.

The centile lines delineate data into percentages:

the 50th centile represents the mean (average);

25% of children are below the 25th centile. The

normal range (approx. ±2 SD from the mean) lies

between the 3rd and the 97th centile.

Normal Growth: Simple Rules of Thumb

Approximate average expected weight gain for a

healthy term infant:

• 200 g/week in the first 3 months


• 130 g/week in the second 3 months


• 85 g/week in the third 3 months


• 75 g/week in the fourth 3 months


• Birth weight usually doubles by 4 months and
  triples by 12 months
  Length:


• Increases by 25 cm in the first year


• Increases by 12 cm in the second year


• By 2 years, roughly half the adult height is at-
  tained
  Head circumference:


• Increases by 1 cm/month in the first year


• Increases by 2 cm in the whole of the second
  year


• Will be 80% of adult size by 2 years
  (N.B.: g row t h rates va r y considerably bet ween
  children; these figures should be used in con-
  junction with growth charts.)

P a t t e r n s o f G r o w t h

Birth weight/centile is not always a good guide to

genetic potential; some infants cross centile lines

in the first few months of life (‘catch down’), but

from then on continue to follow along a lower

centile. The maximum weight centile achieved

between 4 and 8 weeks is the best predictor of

weight centile at 12 months. Infants born below

the 10th centile for gestational age may either

Fig. 6. Triceps skinfold thickness taken with Harpenden
callipers at the mid upper arm allows estimation of fat
energy stores and is useful for serial monitoring.

Koletzko B, et al. (eds): Pediatric Nutrition in Practice. World Rev Nutr Diet. Basel, Karger, 2015, vol 113, pp 6–13

DOI: 10.1159/000360311