Effect of fetal and infant growth on respiratory symptoms in preterm-born children

ObjectivesFetal growth and rapid postnatal weight gain are associated with adverse respiratory outcomes in childhood. However, the preterm-born population is less well studied. We assessed if the increased respiratory symptoms associated with altered fetal growth and infant weight gain were mediated by early factors. Study DesignWe used data from our cohort of preterm- and term-born (n=4284 and 2865) children, aged 1-10 years. Respiratory outcomes obtained from a respiratory questionnaire were regressed on measures of fetal growth and infant weight gain, defined as >0.67SD change in fetal measurement or weight between birth and nine months of age, then adjusted for covariates. We used mediation analysis to investigate which variables were effect modifiers. ResultsAccelerated fetal growth between the 1st trimester and birth (OR 2.01; 95%CI 1.25, 2.32), and between the 2nd trimester and birth (1.60; 1.15, 2.22) was associated with increased wheeze-ever in preterm-born children. Rapid infant weight gain was associated with increased wheeze-ever (1.22; 1.02, 1.45); children born 32 weeks' gestation exhibiting rapid weight gain had fivefold higher risk of wheeze-ever compared to term-born without weight gain. Current maternal smoking and gestational age were identified as candidate mediating effects. ConclusionsOur study suggested that antenatal and postnatal growth rates are important for future respiratory health in preterm-born children, and that their effects may be mediated by modifiable factors. Minimizing exposure to environmental pollutants, especially maternal tobacco smoking, may improve outcomes.