Objective: To assess the growth pattern of full term low and adequate birth weight infants during the first two years of life and to identify the determinants at the time of the greatest growth deceleration.
Methods: A prospective cohort study was conducted with 148 full term infants in five small towns of the state of Pernambuco, Northeastern Brazil. Newborns were recruited from maternities between January 1993 and January 1994 and their anthropometric measurements were taken at one, two, four, six, 12 and 24 months of life. Risk factors were analyzed using multivariable linear regression.
Results: The increment of mean weight-for-age and length-for-age were more evident for low birth weight when compared with adequate weight infants, especially during the first two months after birth. From this point onward it was observed a progressive mean growth deceleration in both indexes up to 12 months of life. All infants had similar weight and length growth patterns. However, adequate birth weight infants remained in an upper level. Socioeconomic variables explained 23% of variation for weight-for-age, followed by 4% for birth weight. Socioeconomic condition was also the factor mostly affecting length-for-age, explaining 28% of its variation, followed by birth weight, maternal height and diarrhea.
Conclusions: The study results suggest that interventions aiming to adequate growth should focus on prenatal care and social and environmental factors during childhood as a way of ensuring full expression of the genetic potential of this population.