Fetal growth, early postnatal growth and motor development in Pakistani infants

Background Studies have often compared the postnatal motor development of ‘small’ versus ‘normal’ newborns. Not much is known about the associations between a broad spectrum of size at birth and motor development. The effect of early postnatal growth on motor development is little researched. Growth failure in terms of shortness and thinness should be differentiated, but not many studies have the data for this analysis. Methods This is a longitudinal study of infants born in Lahore, Pakistan, between 1984 and 1987. Age at commencement of independent walking and age at ‘building a 3-cube tower’ were taken as indicators of gross and fine motor development, respectively. Size at birth was captured by length and thinness as continuous variables; postnatal growth from birth to 6 months of age was measured by changes in length and thinness. Adjustment for covariates and handling of censored cases were performed by generalized log gamma regression. Results Thinness at birth and postnatal stunting and wasting had a linear, inverse association with gross motor development (each P < 0.05). Birth length had a non-linear, inverse association with this outcome (P < 0.05). Birth length, thinness at birth and postnatal wasting had a linear, inverse association with fine motor development (each P < 0.05). Conclusion Both fetal and early postnatal growth over a broad spectrum may affect infants' motor development. It is not just the babies who were very small at birth that suffered. Birth length appeared to be more influential than other anthropometric indicators. KEY MESSAGES shortness at birth, thinness at birth and postnatal wasting were inversely related messages to the age at commencement of milestones of gross and fine motor development. postnatal stunting was inversely related to the age at commencement of a gross motor milestone. variation of growth over a broad spectrum was related to the outcome measures; it was not just the babies who were very small that suffered. shortness at birth appeared to be more important than other aspects of fetal and early postnatal growth in determining motor development.