Roles of the underlying cause of delivery and gestational age on long-term child health

Background Clinical conditions leading to delivery are heterogeneous. However, most studies examining the short- and long-term consequences of birth on child health only consider gestational age at delivery, not the underlying cause. Objective To examine the effect of both gestational age at delivery and underlying cause of delivery on child health outcomes. Methods This population-based retrospective cohort study of singleton infants born in Alberta (April 2004-March 2005) used linked administrative and perinatal data to identify birth subtypes by underlying cause (infection/inflammation (I/I), placental dysfunction (PD), both, or neither), gestational age at delivery, and child health outcomes (neonatal morbidity and mortality, paediatric complex chronic conditions, and neurodevelopmental disorders and disabilities). Poisson regression with robust variance was used to assess differences in the (adjusted) risk ratio (RR) of each outcome by gestational age, and by cause of delivery. The roles of gestational age and cause of delivery were examined using mediation analysis methods. Results A total of 38,192 children were included, with 66.7% experiencing neither I/I nor PD (I/I: 4.0%, PD: 27.5%, both: 1.8%). Infants born preterm had higher risk of all outcomes compared to those born at term and late-term. Infants with exposure to both causes had higher risk of all outcomes (neonatal morbidity, RR 8.96, 95% confidence interval [CI] 7.55, 10.63; paediatric complex chronic conditions, RR 3.94, 95% CI 3.08, 5.05; and neurodevelopmental disorders, RR 1.58, 95% CI 1.37, 1.84). The effect of underlying cause of delivery on child health outcomes was partially explained by gestational age, more in cases involving I/I than in those involving PD alone. Conclusions Short- and long-term child health outcomes differ by the underlying cause leading to delivery, as well as the gestational age at delivery. Having a clearer prognosis for infants may promote the use of clinical interventions earlier for children at increased risk.