3  Pediatric Anthropometry

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Published

June 6, 2025

3.1 Introduction

Pediatric anthropometry is the scientific measurement of the physical dimensions and composition of the human body in children. It is a fundamental component of growth monitoring and nutritional assessment, playing a crucial role in evaluating child health. For medical students and healthcare providers in Ghana, mastering anthropometry is essential for identifying malnutrition, developmental issues, and chronic diseases in children. This clinical note will cover the principles, techniques, indicators, interpretation, and clinical application of pediatric anthropometry, with special attention to the Ghanaian context.

3.2 Objectives of Paediatric Anthropometry

  1. Assess growth and nutritional status
  2. Monitor development over time
  3. Detect early signs of undernutrition or overnutrition
  4. Evaluate the impact of health and nutrition interventions
  5. Assist in diagnosing systemic illnesses
  6. Provide evidence for public health surveillance and policy making

3.3 Key Anthropometric Measurements in Children

1. Weight

  • Importance: Reflects body mass and is sensitive to acute changes in health and nutrition.
  • Equipment:
    • Infants: Electronic infant scale or beam balance (accurate to ±10g).
    • Older children: Digital or beam scale (accurate to ±100g).
  • Procedure:
    • Remove clothing and shoes.
    • For infants, weigh naked or with minimal clothing.
    • Ensure the scale is calibrated and on a flat surface.
  • Interpretation:
    • Compare with WHO growth standards using Weight-for-Age (WFA), Weight-for-Height (WFH), and Body Mass Index (BMI).

2. Length/Height

  • Length (children <2 years):

    • Measured using an infantometer.
    • Child lies supine with head held against the fixed headboard and legs fully extended.

  • Height (children ≥2 years):

    • Use a stadiometer or wall-mounted measuring board.
    • The child stands erect without shoes, heels together, and looks straight ahead

  • Accuracy: ±0.1 cm

  • Interpretation:

    • Compare with Height-for-Age (HFA) standard.
    • Used to detect stunting (chronic malnutrition)

3. Mid-Upper Arm Circumference (MUAC)

  • Importance: A rapid screening tool for acute malnutrition in children aged 6–59 months.

  • Equipment: MUAC tape (color-coded for easy interpretation).

  • Procedure:

    • Locate the midpoint between the acromion and the olecranon process.
    • Measure the circumference of the left upper arm

  • Interpretation:

    • MUAC <11.5 cm: Severe Acute Malnutrition (SAM).
    • 11.5–12.5 cm: Moderate Acute Malnutrition (MAM).
    • ≥12.5 cm: Normal

4. Head Circumference

  • Importance: Reflects brain growth, especially in the first two years.
  • Equipment: Non-stretchable measuring tape.
  • Procedure:
    • Place the tape above the eyebrows and ears, and around the occipital prominence.
  • Interpretation:
    • Compare with age- and sex-specific World Health Organization (WHO) standards.
    • Used to identify microcephaly or macrocephaly.

5. Chest Circumference

  • Less frequently used.
  • Normally, head circumference exceeds chest circumference at birth; both become equal by 1 year.
  • May help in nutritional assessments.

6. Body Mass Index (BMI)

  • Formula: BMI = Weight (kg) / Height² (m²).
  • Use: Detects overweight and obesity.
  • Interpretation (children ≥5 years):
    • <5th percentile: Underweight.
    • 5th–85th percentile: Normal.
    • 85th–95th percentile: Overweight.
    • 95th percentile: Obese.

3.4 Anthropometric Indices and Indicators

These indices compare the child’s measurement with reference values to classify nutritional status.

1. Weight-for-Age (WFA)

  • Detects underweight.
  • Sensitive to both acute and chronic malnutrition.
  • Limitation: Does not distinguish between stunting and wasting

2. Height-for-Age (HFA)

  • Reflects linear growth.
  • Low HFA = Stunting (chronic malnutrition).
  • Not useful for detecting acute malnutrition.

3. Weight-for-Height (WFH)

  • Identifies wasting (acute malnutrition).
  • Independent of age.
  • Used in emergencies and hospital settings.

4. BMI-for-Age

  • Preferred index for children over 5 years.
  • Classifies thinness, normal weight, overweight, and obesity.

5. Head Circumference-for-Age

  • Used in infants to assess brain development and detect congenital anomalies or infections (e.g., hydrocephalus, microcephaly).

3.5 WHO Growth Standards

  • WHO standards are based on healthy children from multiple countries, including Ghana.
  • Charts available for boys and girls separately.
  • Include percentiles and Z-scores (standard deviations from the median).

Z-Score Interpretation:

Z-score Classification
≥ –1 SD to ≤ +1 SD Normal growth
< –2 SD Moderate malnutrition
< –3 SD Severe malnutrition
> +2 SD Overweight
> +3 SD Obese

Z-scores are preferred over percentiles for clinical and public health use because they are more statistically robust.

3.6 Anthropometry in Ghana: Local Context

Nutritional Issues in Ghana

  • Undernutrition: Common in Northern and some rural regions due to food insecurity.
  • Stunting: Affects ~19% of children under 5 (per recent DHS data).
  • Wasting: Acute malnutrition is less common but serious in emergencies.
  • Overweight/Obesity: Emerging problem in urban areas

Common Causes:

  • Poverty, food insecurity, and poor weaning practices.
  • Frequent infections (e.g., malaria, diarrhea).
  • Inadequate maternal education.
  • Cultural beliefs affecting feeding.

Public Health Programs:

  • Child Welfare Clinics (CWC): Regular growth monitoring, including weight and MUAC measurements.
  • Community-Based Management of Acute Malnutrition (CMAM).
  • School feeding programs.
  • Health education on infant and young child feeding (IYCF).

3.7 Clinical Applications

3.7.1 Case Scenarios:

Case 1: Underweight Child

  • Age: 18 months
  • Weight: 6.5 kg
  • WFA Z-score: –3.2
  • MUAC: 11.2 cm
  • Diagnosis: Severe underweight and severe acute malnutrition.
  • Action: Admit to NRU (Nutritional Rehabilitation Unit); initiate therapeutic feeding

Case 2: Overweight Child

  • Age: 10 years
  • Weight: 40 kg
  • Height: 1.35 m
  • BMI: 21.9 → >95th percentile
  • Diagnosis: Childhood obesity
  • Action: Diet and lifestyle counseling; screen for comorbidities like hypertension, type 2 diabetes.

3.8 Challenges in Anthropometric Assessment in Ghana

  • Equipment shortages: In rural clinics, proper weighing scales or stadiometers may be lacking.
  • Lack of training: Some healthcare workers and students may not receive adequate training in accurate measurement techniques.
  • Poor record-keeping: Growth monitoring charts are often incomplete or misinterpreted.
  • Cultural barriers: Some communities resist exposing children for weighing or measurement.
  • Inconsistent standards: Some facilities still use outdated or non-standard growth charts.

3.9 Tips for Medical Students

  1. Practice correct technique: Learn hands-on from skilled clinicians.
  2. Use WHO charts: Understand how to plot and interpret Z-scores.
  3. Observe growth trends: One-time measurements are less informative than trends over time.
  4. Correlate with clinical findings: Anthropometry should complement physical exam and dietary history.
  5. Educate caregivers: Explain growth status in simple language; encourage regular CWC visits.

Summary Table of Key Measures

Measurement Age Group Tool Indicator Interpretation
Weight All Infant/Beam Scale WFA, WFH, BMI Underweight, wasting, obesity
Length <2 yrs Infantometer HFA Stunting
Height ≥2 yrs Stadiometer HFA, BMI Stunting, overweight
MUAC 6–59 months MUAC tape Acute malnutrition SAM, MAM
Head Circumference 0–2 yrs Measuring tape HC-for-age Micro/macrocephaly

3.10 Conclusion

Pediatric anthropometry is an indispensable clinical tool for assessing child health and nutrition. In the Ghanaian context, it is vital for early detection of malnutrition and guiding appropriate interventions. As a medical student, mastering these measurements, understanding their interpretation, and applying them in both clinical and public health settings are crucial skills. Consistent, accurate anthropometric assessment can drastically improve child survival and long-term developmental outcomes in Ghana.