Short-term growth in head circumference and its relationship with supine length in healthy infants

Abstract

Background: Daily changes in height have been found to be a non-linear process. Its exact pattern is still controversial. In previous studies on 34 healthy children aged 0.32–12.99 years, we found that growth is a tri-phasic process: stasis, steep changes (or saltation) and continuous growth. There is very little information in the literature about daily changes in head circumference.Aim: The present study analysed growth in head circumference and supine length in eight healthy infants.Subject and methods: Supine length and head circumference was measured five times a week during 151 days. Mean intra-observer technical error of measurement (TEM) for head circumference and supine length were 0.10 and 0.15 cm, respectively; smoothing techniques used were based on the TEM with a hard rejection criterion.Results: The three types of events previously found in supine length are also present in head circumference. The number of steep changes was greater in supine length than in head circumference.Conclusion: Growth is a discontinuous and irregular process, present not only in long bones but also in skull bones. Although long-term growth curves of head circumference and supine length are different, when measured on a daily basis findings suggest that skull and long bones have a common pattern; the physiological basis needs future research.