Growth and neuromotor development are the most distinctive characteristics of pediatrics which distinguish children from adults. Assessment of growth and development helps in identifying normal progress as well as detecting early deviations that may require medical attention.
Physical growth after birth depends on the interaction between genetic factors and environmental influences such as nutrition and infections.
| Age | Average Weight Gain |
|---|---|
| First 3 months | 30 g/day (≈ 800 g/month) |
| 3–6 months | 20 g/day (≈ 600 g/month) – Birth weight doubles |
| 6–9 months | 15 g/day (≈ 400 g/month) |
| 9–12 months | 12 g/day (≈ 300 g/month) |
| 1–3 years | 8 g/day (≈ 3 kg/year) – Birth weight quadruples |
| 4–6 years | ≈ 2 kg/year until puberty |
| Adolescence | Girls: 3–4 kg/year | Boys: 6–7 kg/year |
Weight (kg) = (Age in years + 3) × 2.3
| Age | Height Gain |
|---|---|
| At Birth | 50 cm |
| 1st Year | +25 cm (≈ 75 cm) |
| 2nd Year | +12.5 cm (≈ 87.5 cm) |
| 3rd Year | 7.5–10 cm |
| 3–12 years | 5–7.5 cm/year |
| Adolescence | Girls: 8 cm/year | Boys: 10 cm/year |
Height (cm) = (Age in years × 6) + 77
| Age | Head Circumference |
|---|---|
| Birth | 35 cm |
| Birth–3 months | +2 cm/month |
| 3–6 months | +1 cm/month |
| 9–12 months | +0.25 cm/month |
| 1 year | 46–47 cm |
| 2 years | 48 cm |
| 5 years | 50–51 cm |
| 12 years | 52 cm |
