Spirometric lung function in school-age children: effect of intrauterine growth retardation and catch-up growth

Few studies have investigated childhood respiratory outcomes of intrauterine growth retardation (IUGR), and it is unclear if catch-up growth in these children influences lung function.

We determined if lung function differed in 8- to 9-year-old children born at term with or without growth retardation, and, in the growth-retarded group, if lung function differed between those who did and those who did not show weight catch up.

Caucasian singleton births of 37 weeks or longer gestation from the Avon Longitudinal Study of Parents and Children (n = 14,062) who had lung spirometry at 8-9 years of age were included (n = 5,770).

Infants with gestation-appropriate birthweight (n = 3,462) had significantly better lung function at 8-9 years of age than those with IUGR (i.e., birthweight <10th centile [n = 576] [SD differences and confidence intervals adjusted for sex, gestation, maternal smoking during pregnancy, and social class: FEV(1), -0.198 (-0.294 to -0.102), FVC, -0.131 (-0.227 to -0.036), forced midexpiratory flow between 25 and 75% of vital capacity -0.149 (-0.246 to -0.053)]). Both groups had similar respiratory symptoms. All spirometry measurements were higher in children with IUGR who had weight catch-up growth (n = 430) than in those without (n = 146), although the differences were not statistically significant. Both groups remained significantly lower than control subjects. Growth-retarded asymmetric and symmetric children had similar lung function.

IUGR is associated with poorer lung function at 8-9 years of age compared with control children. Although the differences were not statistically significant, spirometry was higher in children who showed weight catch-up growth, but remained significantly lower than the control children.