Small for gestational age, term babies, in the first six years of life.

The cognitive development and behaviour in the first six years of life of small for gestational age (SGA) babies born at term are reviewed. Differences in sample selection and confounding factors associated with socio-economic background, perinatal complications and biased follow-up make the interpretation of results and the comparison of studies difficult. Studies of infants (< 12 months) generally do not show any differences between SGA babies and controls. One study, carried out in Brazil and including comprehensive data on socio-economic background, parental literacy and infant stimulation, showed that low birth weight (LBW) babies were more vulnerable to effects of the environment than normal birth weight (NBW) babies, thus illustrating the importance of looking for interactions between covariates, rather than controlling for them. Deficits begin to appear in the second year of life, but are mainly found in high-risk subgroups. In all three studies of SGA children tested at 3 years of age, the SGA children had lower scores than NBW controls. SGA children tested between 4 and 7 years had generally lower scores than NBW, but differences were smaller and sometimes did no longer reach statistically significant levels. Some recommendations are made for future studies.