In pediatric medicine, growth charts are essential for diagnosing developmental anomalies or confirming optimal growth. For decades, local growth charts based on historical data were the norm. In 2006, the World Health Organization (WHO) released a groundbreaking reference dataset that redefined the global standard. Here is the science behind the WHO standards.
The Multicentre Growth Reference Study (MGRS)
The WHO standards are not merely a collection of national height and weight averages. Instead, they are based on the Multicentre Growth Reference Study (MGRS), a rigorous study conducted between 1997 and 2003. The study tracked 8,440 healthy children from diverse ethnic backgrounds and environments: Brazil, Ghana, India, Norway, Oman, and the United States.
Instead of documenting how children grow in a single country, the WHO MGRS was designed to describe how children should grow when their nutritional, health, and environmental needs are met.
Key Criteria of the Study
To establish a clean, prescriptive reference curve, the children selected for the MGRS met strict health conditions:
- Breastfeeding: Exclusive or predominant breastfeeding for at least 4 months, and continued breastfeeding for at least 12 months.
- Maternal Non-smoking: Mothers did not smoke before, during, or after pregnancy.
- Optimal Environment: Low altitude, no exposure to high pollution, and access to clean water and healthcare.
- Immunization: Full compliance with routine childhood immunizations.
Why This Matters for Parents
Because the WHO standards are prescriptive, they serve as a proactive health standard rather than a descriptive average. They prove that babies from different parts of the world grow remarkably similarly when given the same healthy start in life, regardless of genetic heritage.
By using the WHO standards as a benchmark, pediatricians and parents can identify deviations in height-for-age, weight-for-age, and BMI-for-age earlier, ensuring prompt nutritional or medical intervention when needed.