Growth and Development
Frameworks
Growth and development questions reward a structured approach: measure, plot, compare with the expected trajectory, and ask whether the child is growing and developing in a coherent pattern. Plot length/height, weight, weight-for-length or BMI, and head circumference on the correct chart. Use WHO standards for children under 2 years and CDC charts for ages 2 and older in the US; use corrected age for preterm infants until 24 months. Know the major motor, language, social, and cognitive milestones, but remember that ranges are wide. The key distinction is delay versus regression: loss of skills is always a red flag and prompts urgent evaluation.
Traps
Examiners test isolated versus global delay, asymmetric versus symmetric growth restriction, and constitutional delay versus endocrine disease. A child crossing two major centile lines, falling below the expected curve, or showing dysmorphic features needs investigation. Do not diagnose intellectual disability from a single milestone; assess vision, hearing, language exposure, and social environment. Head circumference that is crossing centiles or disproportionate to length is a trap for hydrocephalus or microcephaly.
Worked example
An 18-month-old former 28-week preterm infant is not walking. Corrected age is about 15 months, so this is less concerning if other skills are appropriate; however, not bearing weight, asymmetric tone, or regression warrants referral. Rule of thumb: correct for prematurity until 24 months, and treat loss of milestones as urgent.