Article Text
Abstract
Objective Increasing evidence suggests that intrauterine growth retardation (IUGR) is associated with long-term morbidities, including respiratory outcomes. The relationship between IUGR and lung function has been studied in adults, but few studies have investigated childhood respiratory outcomes and it is unclear if catch-up growth in these children influences lung function. We investigated the hypothesis that lung function differs in 8- to 9-year-old children born at term between those that were within normal weight bands and those that had growth retardation. Additionally, in the growth-retarded group, we investigated if lung function differed between those who did and those who did not show weight catch up.
Design The Avon Longitudinal Study of Parents and Children birth cohort.
Participants The 5770 Caucasian singleton births of 37 weeks or longer gestation who had lung function assessed at 8–9 years. We classified 576 infants as IUGR as their gestation-appropriate birthweight fell below the 10th centile. This group was compared with those 3462 non-IUGR infants whose birthweights fell between the 20th and 80th centiles.
Main outcome measure and results The non-IUGR infants had significantly better lung function at 8–9 years of age than those with IUGR. The differences between the standardised (z) lung function values, adjusted for sex, gestation, maternal smoking during pregnancy, and social class, and 95% CI were FEV1: −0.198 (−0.294 to −0.102); FVC: −0.131 (−0.227 to −0.036); FEF 25–75: −0.149 (−0.246 to −0.053). The groups had similar respiratory symptoms. Catch-up growth for weight was defined as an increase in z score of at least 0.67 between birth and ages 8–9 years. For the IUGR children, 430 caught up and 146 did not. All spirometry measurements were higher in IUGR children who experienced catch-up growth than in those without, 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.
Conclusion We concluded that 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 in the control children.