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

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.