General Pediatrics: Growth, Development, and the Well-Child Visit
Core concepts
General pediatrics questions reward a developmental and preventive frame rather than an adult-disease frame. Know the growth chart mechanics: weight-for-age, length/height-for-age, weight-for-length (under 2 years) and BMI-for-age (2 years and older), and head circumference through about 36 months. Understand normal growth velocity changes with age (fastest in infancy, slower prepubertal, pubertal spurt) and the difference between constitutional delay and pathologic failure to thrive (weight falling before length, then head circumference, is the classic sequence in undernutrition).
Developmental milestones should be organized by domain (gross motor, fine motor, language, social) and by red-flag windows: social smile by 2 months, no words by 16 months, no two-word phrases by 24 months, loss of skills at any age. Screening tools (developmental surveillance at every visit, autism-specific screening at 18 and 30 months) are fair game.
Traps
- Confusing percentile crossing (concerning if two major centile lines crossed downward) with a single low percentile in a constitutionally small but thriving child.
- Assuming a milestone is delayed when it is simply at the outer edge of normal (walking independently up to 18 months).
- Missing that regression is always abnormal.
- Forgetting immunization schedule timing and contraindications (live vaccines in immunocompromise).
Rule of thumb
Use the red-flag-first approach: if a milestone is missing at the screening age, refer for evaluation rather than "watch and wait" beyond one interval. A useful anchor: birth weight doubles by 4–5 months and triples by 12 months; length increases ~50% by 12 months.