The first two years have a rhythm: rapid weight gain, a head that grows fastest of all, and a length curve that stretches steadily. Here is the journey by age.
Birth to 3 months
The fastest phase. Weight nearly doubles expectations in months, head circumference grows about 2 centimeters a month, and the newborn weight dip gives way to steady gains.
3 to 6 months
Growth stays strong but the pace begins to ease. Length continues steadily, head growth slows slightly, and most babies settle into a clear percentile band.
6 to 12 months
The steady middle of year one. Weight gain slows, length and head growth continue, and the curve becomes a reliable predictor of the toddler pattern ahead.
12 to 24 months
The toddler slowdown: growth drops to a few centimeters a year, appetite swings, and the WHO curve shows a much flatter, steadier line.
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