Length is the slowest-moving of the three growth measures, which is exactly why it matters: height problems show up slowly and quietly, so a steady curve over months is the signal that everything is on track.
Length first, height later
Until a child can stand reliably, pediatricians measure length lying down and plot it on a length-for-age curve. Once standing, the same child is measured as height. The two scales differ slightly, and the WHO chart treats them separately.
What the curve shows
Babies grow about 25 centimeters in the first year, then around 12 in the second. The WHO length-for-age curve captures that slowing curve — and a child who stays near their percentile line through it is growing exactly as expected.
Reading it with weight
Pediatricians rarely read height alone. A child whose weight is fine but whose length drifts down across lines over several months is the pattern that gets attention. Height is the slow signal; weight is the fast one.
One chart, both measures
GrowChart plots length and height on the official WHO curves and keeps the full history, so the slow, quiet story of height is visible at every visit.
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