Respiratory distress syndrome in moderately late and late preterm infants and risk of cerebral palsy: a population-based cohort study

Objectives: Infant respiratory distress syndrome (IRDS) is a known risk factor for intracerebral haemorrhage/intraventricular haemorrhage (ICH/IVH) and periventricular leucomalacia. These lesions are known to increase the risk of cerebral palsy (CP). Thus, we wanted to examine the long-term risk of CP following IRDS in moderately late and late preterm infants. Design: Population-based cohort study. Setting: All hospitals in Denmark. Participants: We used nationwide medical registries to identify a cohort of all moderately and late preterm infants (defined as birth during 32-36 full gestational weeks) born in Denmark in 1997-2007 with and without hospital diagnosed IRDS. Main outcomes measures: We followed study participants from birth until first diagnosis of CP, emigration, death or end of follow-up in 2014. We computed the cumulative incidence of CP before age 8 years and used Cox's regression analysis to compute HRs of IRDS, comparing children with IRDS to those without IRDS. HRs were adjusted for multiple covariates. Results: We identified 39 420 moderately late and late preterm infants, of whom 2255 (5.7%) had IRDS. The cumulative incidence of CP was 1.9% in infants with IRDS and 0.5% in the comparison cohort. The adjusted HR of CP was 2.0 (95% CI 1.4 to 2.9). The adjusted HR of CP was 12 (95% CI 4.5 to 34) in children with IRDS accompanied by a diagnosis of ICH/IVH. After restriction to children without diagnoses of perinatal breathing disorders other than IRDS, congenital heart disease and viral or bacterial infections occurring within 4 days of birth, the overall adjusted HR was 2.1 (95% CI 1.4 to 3.1). Conclusions: The risk of CP was increased in moderately late and late preterm infants with IRDS compared with infants without IRDS born during the same gestational weeks.