Introduction
Growth is one of the most sensitive indicators of a child’s health and nutritional status. A frequently encountered clinical scenario illustrates the importance of objective assessment: A 2-year-old boy weighs 8 kg and is 78 cm tall. His mother reports that he eats well. Is this child normal? Clinical examination alone cannot answer this question accurately. The assessment of growth requires comparison with standardized reference data over time. The scientific and practical solution to this dilemma is the growth chart .
A growth chart, also called the Road to Health Chart, is a graphical representation of a child’s physical growth plotted against age. It was originally designed by David Morley and later modified and standardized by the World Health Organization (WHO). The primary purpose of the growth chart is longitudinal follow-up. It allows health workers and clinicians to interpret changes in growth over time rather than relying on a single measurement.
Growth monitoring is an essential component of child health services, preventive pediatrics, and community medicine. It enables early identification of growth faltering, undernutrition, and obesity. Early detection allows timely intervention, preventing irreversible consequences such as stunting, cognitive impairment, and increased morbidity.
Thus, growth charts are not merely records of weight and height; they are dynamic clinical tools that bridge preventive and curative pediatrics.
WHO Growth Standards (2006)
The modern era of growth assessment began with the release of the WHO Child Growth Standards (2006). These standards were developed following the Multicentre Growth Reference Study (MGRS), conducted between 1997 and 2003 across six countries: Brazil, Ghana, India, Norway, Oman, and the USA .
Rationale for New Standards
Earlier growth references, such as the NCHS/CDC charts, were based predominantly on formula-fed infants from high-income settings. These references described how children grew in specific populations rather than how children should grow under optimal conditions. Therefore, WHO aimed to create standards, not references — representing optimal growth patterns.
Study Population
The MGRS included data from 9,440 healthy breastfed infants and young children aged 0–60 months. Inclusion criteria ensured:
- Optimal environmental conditions
- Non-smoking mothers during and after pregnancy
- Exclusive or predominant breastfeeding
- Adequate healthcare access
- Absence of significant socioeconomic constraints
This design ensured that the standards represented physiological growth under ideal circumstances.
Key Features of WHO Standards
- Applicable globally regardless of ethnicity or socioeconomic status.
- Separate standards for boys and girls.
- Cover age range 0–60 months.
- Provide percentiles and Z-score curves.
- Include multiple growth indicators:
- Length/Height-for-Age
- Weight-for-Age
- Weight-for-Length
- Weight-for-Height
- BMI-for-Age
Z-Scores and Standard Deviations
Growth assessment using WHO charts is based on Z-scores (Standard Deviation scores):
- 0 SD → Median
- −2 SD → Moderate undernutrition
- −3 SD → Severe undernutrition
- +2 SD → Overweight
- +3 SD → Obesity
Interpretation:
- Between −2 SD and +2 SD → Normal growth
- Below −2 SD → Undernutrition
- Below −3 SD → Severe malnutrition
An important principle emphasized in WHO standards is that the direction of the growth curve is more important than the absolute plotted point . A downward crossing of centiles or flattening indicates growth failure, even if the child is still within the “normal” range.
WHO Anthro Software
WHO developed the WHO Anthro software for:
- 0–5 years age group
- 5–15 years age group
This software calculates Z-scores automatically and minimizes calculation errors.
Types of Growth Charts
Growth charts can assess different anthropometric indices. Each has specific clinical significance.
| Type of Growth Chart | Growth Indicator Used | Clinical Utility |
|---|---|---|
| Weight-for-Age (WFA) | Weight compared with age | Sensitive indicator of undernutrition |
| Height-for-Age (HFA) | Height compared with age | Detects stunting |
| Weight-for-Height (WFH) | Weight compared with height | Detects wasting |
| BMI-for-Age | BMI adjusted for age | Identifies overweight/obesity |
Weight-for-Age charts are considered more sensitive in early detection because weight changes rapidly with acute nutritional deficits .
1. Weight-for-Age (WFA)
- Composite index.
- Cannot differentiate between stunting and wasting.
- Best for routine growth monitoring in under-five children.
2. Height-for-Age (HFA)
- Reflects chronic malnutrition.
- Low HFA indicates stunting.
- Often associated with long-term socioeconomic deprivation.
3. Weight-for-Height (WFH)
- Independent of age.
- Reflects acute malnutrition (wasting).
- Useful in emergency settings.
4. BMI-for-Age
- Detects overweight and obesity.
- Increasingly important due to rising childhood obesity.
Growth Charts Used in India
India officially adopted the WHO 2006 Growth Standards in 2009 for use in the National Rural Health Mission (NRHM) and Integrated Child Development Services (ICDS) programs .
Implementation in India
- Growth charts included in the Mother and Child Protection (MCP) card.
- Used by Anganwadi workers and Auxiliary Nurse Midwives.
- Applied in community-based nutrition programs.
- Utilized for research and surveillance.
Interpretation Zones in Indian Charts
- Normal Zone: Between −2 SD and +2 SD.
- Undernutrition: Below −2 SD.
- Severe Undernutrition: Below −3 SD.
The Indian charts emphasize that the trend of the curve is more important than the actual dot position .
Growth Faltering
Flattening or downward trend of the weight curve is the earliest sign of Protein Energy Malnutrition (PEM). This observation is critical for early intervention.
Components of Growth Charts
A standard growth chart consists of:
- Identification details
- Age axis (X-axis)
- Measurement axis (Y-axis)
- Reference curves
- Color coding
- Growth trend
X-axis (Age)
- Marked in completed months.
- Accurate age calculation is essential.
- Even 1–2 months’ error may misclassify nutritional status.
Y-axis (Measurement)
- Weight (kg)
- Height/Length (cm)
- BMI (kg/m²)
Reference Curves
Standard lines drawn based on reference population. They usually include:
- 0 SD (Median)
- −2 SD
- −3 SD
- +2 SD
- +3 SD
These allow statistical comparison of an individual child with a healthy reference population.
Uses of Growth Charts
Growth charts serve multiple functions in public health and clinical medicine.
1. Growth Monitoring
Regular plotting identifies deviations early. Recommended frequency:
- Birth to 6 months: Monthly
- 6–12 months: Every 2 months
- 1–3 years: Every 3 months
- 3–5 years: Every 6 months
2. Screening and Diagnostic Tool
- Identify undernutrition.
- Detect severe acute malnutrition.
- Identify obesity trends.
3. Planning and Policy Making
Aggregated growth data help:
- Estimate prevalence of stunting/wasting.
- Guide resource allocation.
- Design ICDS strategies.
4. Educational Tool
- Demonstrates importance of adequate feeding.
- Shows impact of diarrhea on weight loss.
- Encourages breastfeeding.
5. Tool for Action
Health workers take immediate action when:
- Weight falls below −2 SD.
- Curve flattens or declines.
- Crossing of two centile lines downward.
6. Evaluation of Interventions
Used to evaluate:
- Nutrition Rehabilitation Centres.
- ICDS supplementary feeding.
- Deworming and Vitamin A programs.
7. Teaching Tool
Helps medical students understand:
- Malnutrition grading.
- Natural history of PEM.
- Importance of preventive pediatrics.
Interpretation Principles
- Serial measurements are essential.
- A single reading is insufficient.
- Downward crossing of centiles is alarming.
- Upward crossing may indicate obesity.
- Always correlate clinically.
Example Interpretation
A 24-month-old boy weighing 8 kg plotted below −3 SD:
- Severe undernutrition.
- Requires immediate nutritional rehabilitation.
- Screen for infections and feeding problems.
Limitations of Growth Charts
Despite their usefulness, growth charts have limitations .
| Limitation | Explanation |
|---|---|
| Etiology | Shows deviation but not cause |
| Single Reading | Not diagnostic |
| Measurement Errors | Common and impactful |
| Development Delays | Not assessed |
| Micronutrient Deficiency | Cannot detect anemia or vitamin deficiency |
| Acute Illness | May temporarily affect weight |
| Genetics | Does not account for parental stature |
Measurement Errors
Common errors include:
- Incorrect age calculation.
- Faulty weighing scales.
- Improper positioning for length measurement.
These errors can significantly alter classification.
Summary
Growth charts are objective tools for longitudinal assessment of child growth . Their interpretation relies on serial measurements rather than single readings. The direction of the growth curve is more important than the absolute plotted value. WHO growth standards represent optimal growth applicable across populations. Growth charts are effective for screening and monitoring but cannot identify etiology or detect micronutrient deficiencies. Accurate interpretation requires correct age calculation, precise measurement, and clinical correlation.
MCQs
1. A child’s weight is −2.5 SD on WHO chart. This indicates:
A. Normal
B. Moderate undernutrition
C. Severe undernutrition
D. Overweight
Answer: B
2. Which index best reflects chronic malnutrition?
A. Weight-for-Age
B. Weight-for-Height
C. Height-for-Age
D. BMI-for-Age
Answer: C
3. The WHO 2006 standards are based on:
A. Formula-fed infants
B. Mixed population including malnourished children
C. Healthy breastfed children under optimal conditions
D. Only American children
Answer: C
4. Earliest sign of PEM on growth chart:
A. Weight < −3 SD
B. Edema
C. Flattening of weight curve
D. BMI decline
Answer: C
5. Weight-for-Height assesses:
A. Stunting
B. Wasting
C. Obesity only
D. Developmental delay
Answer: B
6. Crossing two centile lines downward suggests:
A. Normal variation
B. Growth acceleration
C. Growth faltering
D. Genetic short stature
Answer: C
7. WHO standards applicable age:
A. 0–12 years
B. 0–60 months
C. 5–15 years only
D. 0–18 years
Answer: B
8. Which cannot be detected by growth chart?
A. Stunting
B. Wasting
C. Anemia
D. Obesity
Answer: C
9. Most sensitive early indicator:
A. Height-for-Age
B. Weight-for-Age
C. BMI-for-Age
D. Head circumference
Answer: B
10. Severe undernutrition defined as:
A. < −1 SD
B. < −2 SD
C. < −3 SD
D. < Median
Answer: C
Below are expanded, high-difficulty, case-based NEET PG MCQs (11–20) from Growth Charts with detailed options and explanations.
11. Growth Faltering with Downward Crossing
An 18-month-old boy was tracking along the 0 SD line for weight-for-age until 12 months. Over the next 4 months, his weight curve crossed two centile lines downward and is now below −3 SD. Height-for-age is at −1 SD. What is the most appropriate interpretation?
A. Chronic malnutrition (stunting)
B. Genetic short stature
C. Severe acute malnutrition with recent growth faltering
D. Normal variation
Answer: C
Explanation:
Rapid downward crossing of centile lines indicates growth faltering. Weight < −3 SD suggests severe undernutrition. Since height-for-age is relatively preserved (−1 SD), this indicates acute malnutrition rather than chronic stunting.
12. BMI-for-Age Interpretation
A 7-year-old girl has BMI-for-age plotted at +3.2 SD on WHO reference chart. Height-for-age is +0.5 SD and weight-for-age is +2.8 SD. Interpretation?
A. Normal growth spurt
B. Overweight
C. Severe acute malnutrition
D. Obesity
Answer: D
Explanation:
BMI-for-age > +3 SD indicates obesity. Overweight is between +2 and +3 SD.
13. Chronic Disease and Growth Pattern
A 5-year-old child with history of untreated congenital heart disease shows height-for-age −3 SD and weight-for-height −1 SD. Most likely pattern?
A. Acute malnutrition
B. Wasting
C. Stunting due to chronic illness
D. Overfeeding
Answer: C
Explanation:
Low height-for-age reflects chronic undernutrition or chronic illness. Weight-for-height relatively preserved suggests long-standing disease affecting linear growth.
14. Acute Illness Effect on Growth Chart
A 2-year-old develops severe diarrhea for 10 days. Weight drops from −1 SD to −2.5 SD. Height-for-age remains unchanged. Mechanism?
A. Stunting
B. Acute weight loss due to dehydration and catabolism
C. Measurement error
D. Genetic short stature
Answer: B
Explanation:
Acute illnesses affect weight immediately. Height does not change in short-term illness.
15. Most Important Principle in Growth Chart Interpretation
A 1-year-old child has weight-for-age at −1.5 SD consistently for 6 months, tracking parallel to reference curve. What is the best interpretation?
A. Moderate malnutrition
B. Severe malnutrition
C. Immediate hospitalization required
D. Likely normal variant with stable growth trend
Answer: D
Explanation:
Stable growth parallel to reference curve is reassuring. Trend is more important than single value.
16. WHO Multicentre Growth Reference Study (MGRS)
Which of the following was NOT a feature of WHO MGRS?
A. Inclusion of breastfed infants
B. Mothers who smoked during pregnancy
C. Multicountry design
D. Optimal environmental conditions
Answer: B
Explanation:
Smoking mothers were excluded to ensure optimal growth conditions.
17. Software for Z-Score Calculation
A pediatrician wants to calculate weight-for-height Z-score for a 3-year-old child. Best recommended tool?
A. WHO Anthro software
B. CDC calculator only
C. IAP percentile chart
D. BMI formula manually
Answer: A
Explanation:
WHO Anthro software is specifically designed for 0–5 years.
18. Single Reading Limitation
A 9-month-old child weighs 6.5 kg plotted at −2.2 SD. No previous records available. Best next step?
A. Diagnose moderate malnutrition immediately
B. Admit for severe malnutrition
C. Repeat measurement and assess serial trend
D. Ignore result
Answer: C
Explanation:
Single reading is insufficient. Serial plotting required before labeling.
19. Familial Short Stature
A 4-year-old boy has height-for-age at −2.5 SD. Weight-for-height normal. Growth curve is parallel to −2 SD line since infancy. Both parents are short. Diagnosis?
A. Severe chronic malnutrition
B. Familial short stature
C. Growth hormone deficiency
D. Cushing syndrome
Answer: B
Explanation:
Parallel growth below −2 SD with short parents suggests familial short stature.
20. MCP Card and Indicator Used in India
In community setting, Anganwadi worker identifies child below −2 SD on MCP card growth chart. This chart primarily uses:
A. Weight-for-Age
B. BMI-for-Age
C. Mid-upper arm circumference
D. Head circumference
Answer: A
Explanation:
Mother and Child Protection (MCP) card in India uses Weight-for-Age chart for routine growth monitoring.
