Anthropometric Measurements

Growth charts are one type of tool to assist physicians in forming an overall picture of the nutritional status of an infant.

• Accurate anthropometric measurements are crucial in charting growth
• The CDC has developed a training course for health care providers who measure and assess growth using the WHO growth charts for children from birth to 2 years

Measuring Recumbent Length

• Accurate length measurement is particularly important for calculating growth velocity.
  
  • Length measurements are best obtained when the child is relaxed and cooperative.
  • If the child is agitated and both legs cannot be held in position, measure with one leg
  • Remove hats, hair adornments, hair buns, shoes, socks
  • Devices for measuring length should be calibrated and accurate to 0.1 cm.
• Two people are required to measure length in infants
  
  • Position infant on measuring board (that has a movable footboard and fixed headboard) with the body flat and the midline centered.
  • One measurer holds the crown of the infant’s head against the headboard with the external auditory meatus and the lower margin of the eye orbit aligned perpendicular to the table
    
    •  When measuring a preterm infant, gently untuck its chin from the chest to position the head properly
  • A second measurer gently flattens the infant’s knees and grips both ankles so the feet are pointing upward and flat on the footboard.
  • Record recumbent length to the last completed 0.1 cm.

Measuring Weight

Various types of scales (infant scales, beam-balance scales, and digital
scales) are available to measure body weight. Scales must be regularly calibrated
to maintain accuracy.

• Remove infant clothing including diaper
  
  • Infant may be weighed in a clean diaper if the scale is first zeroed with the weight of the clean diaper
• Zero the scale
• Place infant supine in the center of the tray making sure the infant is not touching anything but the tray
• Read and record the measurement

Measuring Head Circumference

Head circumference is a proxy measure for brain growth

• Useful screening tool for hydrocephalus in infants
• Measure head circumference with a narrow and nonstretchable measuring tape
  • Remove interfering hair adornments
  • Position the tape on the forehead just above the supraorbital ridges, and wrap around the occiput so that the maximum circumference is obtained, keeping the tape level on both sides
  •  Move the tape slightly up and down to ensure maximum circumference
  • The tape should have sufficient tension to press the hair against the skull
• Record head circumference to the nearest 0.1 cm

Other Anthropometric Measurements for Infants

Arm circumference-for-age

Mid-upper–arm circumference is an indicator of soft tissue growth in all ages.

Measure the right arm at its mid-point using a flexible, nonstretchable tape measure.

• Mark the upper arm midway between the acromion (shoulder) and the olecranon (elbow) on the vertical axis of the upper arm between the lateral and medial surface of the arm with the arm bent at a right angle.
• For the actual circumference measurement, the arm should hang loosely at the side. Pass the tape around the arm at the level marked, perpendicular to the long axis of the arm.
• Position the tape so that it touches but does not compress the skin or alter the contour of the arm.

WHO Multicentre Growth Reference study 2006 and 2007

• Reference data – cross-sectional and longitudinal data from an international sample of healthy children with optimal conditions (eg, breastfed) for growth
• Comments:
  
  • Age – 3 months to 5 years
    
    • Sex specific
    • 3rd to 97th percentile
    • Use with triceps skinfold-for-age curves
• Charts
  
  • Percentiles: Arm circumference-for-age GIRLS 3 months to 5 years (girls) (boys)
  • Z-scores: Arm circumference-for-age GIRLS 3 months to 5 years (girls) (boys)

Skinfold Thickness Measurements

Total or regional body fat can be estimated using skinfold thickness

• Advantages
  
  • Easily and rapidly performed in the clinical setting
  • Safe
  • Reasonably accurate
  • Inexpensive
  • Excellent pediatric reference data are available
• Disadvantages
  
  • Unable to use in neonates due to lack of reference tables
  • Training is required to get reproducible measurements
• Reference charts in both curve and table formats
  
  •  Curve: Triceps skinfold-for-age 3 months to 5 years: percentiles (girls) (boys)
  • Table: Triceps skinfold-for-age 3 months to 5 years: percentiles (girls) (boys)
  • Curve: Triceps skinfold-for-age 3 months to 5 years: z scores (girls) (boys)
  • Table: Triceps skinfold-for-age 3 months to 5 years: z scores (girls) (boys)