Length and Weight Gain in the First Three Months of Life

The relationship between birthweight, birth-length and length and weight gains during the first three months of life for a cohort of 1,210 New Zealand infants was examined. The results of linear multiple regression analysis and analysis of variance showed that there was a complicated relationship between birth size and length and weight gains. Long, light neonates showed considerable weight gain but little length gain; conversely, short, heavy neonates showed considerable length gain but little weight gain. More generally, length gain appeared to be a resultant variable which was negatively related to birth-length but positively related to birthweight. Similarly, weight gain appeared to be a resultant variable which was negatively related to birthweight but positively related to birth-length. The findings suggest that growth in the immediate post-natal period operates in a redistributive fashion which tends to stabilise the relationship between the child’s weight and length