The objective of this study was to compare the development at 24 months of 152 full-term infants, born with low (<2500g) and appropriate birth weight (3000 to 3499g), paired in a proportion of 1:1 by sex and age. Mental and motor development were assessed through the Bayley scale. A variety of sociodemographic and environmental stimulation conditions were also assessed. The infants born with low weight had on average significantly lower mental and motor indexes than those born with appropriate weight (p<0.001), with a difference of 9.1 and 10.2 points, respectively. The multiple linear regression analysis showed that socioeconomic conditions and environmental stimulation explained 11% and 12% of the variation of mental index, and 12% and 9% of motor development, respectively. All together, they explained 23% and 21% of the variation of these indexes. Low birth weight influenced only 3% of the variation of mental index and 5% of motor index.
low birth weight; intra-uterine growth retardation; mental development; motor development; environmental stimulation
