[Growth in head circumference: parent-child correlation and secular trend].

Head circumference is an important growth parameter; it is closely related to brain development in normal infants. Therefore regular meticulous measurements of head circumference can give diagnostic hints of abnormal brain growth, i. e., reduced growth as in severe malnutrition or accelerated as in hydrocephalus, for example. The results presented here are based on the Bonn Longitudinal Study on growth and development; 150 infants (65 preterm and 85 full-term) were measured regularly from birth. Head circumference of the parents was also measured. For the full term infants the highest correlation was found between mother and daughter (r = 0.75), in the preterm infants the highest correlation was seen between mother and son (r = 0.65). In the Bonn Longitudinal Study and in a recent additional Bonn Study no positive secular trend of head circumference was observed which agrees with results of others. Interestingly enough, growth of head circumference behaves completely differently from that of height in the Bonn Study, where a positive secular trend was observed.