Postneonatal Respiratory Morbidity

In this chapter we explore the various respiratory outcomes of preterm neonates, focusing on three morbidities seen in childhood or adulthood: postneonatal pulmonary hypertension, childhood reactive airways disease, and impaired lung function in adulthood. Extreme preterm birth and associated exposures during the perinatal period result in an arrest of lung development leading to a decrease in alveolar number, rarefication of intra-acinar arteries, and abnormal airway smooth muscle contractility. Infants diagnosed with postneonatal pulmonary hypertension have complicated hospitalizations and are at high risk for childhood death. Children born preterm have increased reported wheezing and diminished lung function when compared to term peers. While respiratory symptoms and lung function may improve over time, the trajectory of "catch-up" and subsequent decline in adult lung function has the potential to manifest as early-onset chronic obstructive lung disease in the preterm survivor. Worse lung function, diminished gas diffusion, reduced exercise capacity, and altered cardiac structure and function have been reported in adults born preterm. This chapter addresses early life risk factors, identifies potential therapies, and highlights knowledge gaps to be considered when designing future studies.