Evidence of saltatory growth in infancy

Auxological measurements were taken weekly (n = 10), semi-weekly (n = 20), and daily (n = 3) during the first 21 months of life on a sample of normal infants (21 females and 12 males). The serial length measurements are reported. All subjects grew in length during episodic growth saltuses of short duration, with amplitudes of 0.5-2.0 cm during measurements intervals (1 day to 1 week), separated by periods of no measurable growth (2 days to 2 months). The periods of stasis between growth episodes are not positively associated with illness (P = 0.000). These data support the hypothesis that normal human growth during the first 2 years proceeds by pulsatile growth saltuses of substantial amplitude and rapid duration punctuating static intervals. Individual variability in the amplitude and frequency of growth saltuses may account for variation in attained length and growth velocity.