Differential effects of preterm birth and small gestational age on cognitive and motor development

Abstract

Aims-To determine the diVerential effects of preterm birth and being small for gestational age on the cognitive and motor ability of the child. Methods-A longitudinal cohort of all infants of gestational age ≤ 32 weeks born to mothers resident in the counties of Cheshire and Merseyside in 1980-1 was studied. The children were assessed at the age of 8 to 9 years using the Wechsler Intelligence Scale for Children, the Neale analysis of reading ability, and the StottMoyes-Henderson test of motor impairment. Adequacy of fetal growth was determined by the birthweight ratio-that is, the ratio of the observed birthweight to the expected birthweight for a given gestational age. Children with clinically diagnosed motor, learning or sensory disabilities were excluded. Information on social variables was obtained by a questionnaire completed by the parents. Of the 182 children, 158 were assessed. Results-IQ was positively correlated with birthweight ratio but not with birthweight or gestational age. Motor ability was associated with birthweight, gestational age, and birthweight ratio. Reading comprehension was associated with birthweight ratio, but reading rate and accuracy were best explained by social variables and sex. IQ remained associated with birthweight ratio, after adjusting for maternal education, housing status, and number of social service benefits received. Reading ability was related to these social variables but motor ability was not. Conclusions-The eVects of SGA and preterm birth diVered: SGA was associated with cognitive ability, as measured by IQ and reading comprehension; motor ability was additionally associated with preterm birth. Reading rate and accuracy were not associated with SGA or preterm birth but were socially determined. (Arch Dis Child 1997;76:F75-F81)

Learning disabilities: analysis of 69 children

“…Hutton et al 8 , in a 1997 article, mentioned significant relation between low birth weight with reduced cognitive skills and higher difficulty to read. In prematures, motor skills deficit was predominant 9 .…”

Pre-school cognitive development of very low birth weight preterm children

“…Estes resultados são piores do que os relatados na literatura, que mostram médias mais baixas de QI nos grupos de crianças prematuras de muito baixo peso, porém dentro da faixa de normalidade 2,[12][13][14][15] . Em nosso grupo, a média dos resultados alcançados variou de 65 pontos até 89 pontos nos diferentes escores propostos pelo teste (total, verbal e executivo).…”

Multiple risks for long-term cognitive impairments following preterm birth

“…Several past studies comparing SGA children to both birthweight-matched and GA-matched groups indicated that GA and birthweight made independent contributions to outcome (4,5). Other research also supports independent effects on early neurodevelopmental outcomes of different types of complications, including chronic lung disease, retinopathy of prematurity and perinatal brain insult (6).…”

“…Other research also supports independent effects on early neurodevelopmental outcomes of different types of complications, including chronic lung disease, retinopathy of prematurity and perinatal brain insult (6). It is likely that the effects of SGA vary with the level of GA and that the independent effects of these two factors on cognitive outcomes are obscured by the much larger influences of more extreme preterm birth and attendant neonatal complications (5,7,8). Nevertheless, evidence for independent associations of these several factors with developmental outcomes raises the possibility of distinct pathologies linked to different patterns of cognitive impairment.…”