How did babies grow 100 years ago?

The rates and patterns of growth in weight of European and North American infants have changed over the last 100 years. Since the development and first use of growth charts for postnatal health surveillance a century ago, there appears to have been an increase in the weight of 1-year olds of about 1 kg. Taking into account the higher past rates of infant morbidity and mortality, and poorer quality of artificial feeds, this change is likely to be another expression of the secular increase in physical stature consequent on improved hygiene and nutrition. Using the new WHO (World Health Organisation) standards of infant weight growth, this secular change can be observed for both breast-fed and formula-fed babies. The slower weight growth of the former, both now and in the past compared with modern formula-fed babies, may have implications of our understanding of the risk factors for obesity and cardiovascular disease. The variability of infant growth in time and space, and the plasticity of developmental processes during the life course (fetal life, infancy, puberty and reproduction), means that the WHO infant growth standard should not alone be regarded as an ideal growth trajectory for all babies.