Chronic lung disease of prematurity and intrauterine growth retardation: A population-based study

Objective. To determine the risk of chronic lung disease (CLD) in small for gestational age (SGA) preterm infants in comparison to appropriately grown and large for gestational age (LGA) infants. Methods. Observational study derived from a geographically defined population (Trent Health Region, United Kingdom). All preterm infants of less than or equal to32 completed weeks' gestation born to Trent resident mothers admitted to neonatal units between 1995 and 1999 (inclusive) were included. Birth weight percentiles were created for the whole population, and infants were classified as SGA infants (if <10th percentile), appropriately grown (if between 25th and 75th percentiles-reference group), and LGA infants (if ≥90th centile). Both mortality and CLD rates (using both 28 days' and 36 weeks' postmenstrual age [PMA] definitions) were determined for these groups of infants. Results. Four thousand fifty-one preterm infants ≤32 weeks' gestation were identified. SGA infants showed higher mortality before 28 days' postnatal age and 36 weeks' PMA as compared with reference group infants (odds ratio [OR]: 2.01, 95% confidence interval [CI]: 1.49-2.72; and OR: 2.00, 95% CI: 1.49-2.69), respectively. SGA infants showed a significantly greater risk of developing CLD, both at 28 days' and 36 weeks' PMA as compared with the reference group infants (OR: 1.34, 95% CI: 1.03-1.74; and OR: 1.87, 95% CI: 1.39-2.51), respectively. LGA infants showed a trend toward a reduced incidence of CLD in comparison to the reference group, which was statistically significant for the 36 weeks' definition (OR: 0.76-28 weeks, 95% CI: 0.57-1.01; and OR: 0.55-36 weeks, 95% CI: 0.37-0.81). Conclusions. Fetal growth seems to influence mortality in general and morbidity, attributable to CLD, in particular in preterm infants. SGA preterm infants are at higher risk of death before 28 days' and 36 weeks' PMA and CLD by both definitions. LGA infants show reduced risk of CLD.