Long-term respiratory outcomes of infants born moderate to late preterm

Moderate to late preterm birth, defined as birth between 32 to <37 weeks' gestation, accounts for over 80% of all preterm births globally. Although long-term respiratory outcomes following very and extremely preterm birth are well characterised, the lifelong respiratory consequences of moderate to late preterm birth have received comparatively less attention. Infants born moderate to late preterm experience increased neonatal respiratory morbidity, greater susceptibility to early-life lower respiratory tract infection, and elevated rates of wheeze and physician-diagnosed asthma throughout childhood compared with peers born at term. Individuals born moderate to late preterm demonstrate modest decrements in expiratory airflow relative to those born at term, with emerging evidence of sex-specific trajectories, impaired gas transfer, and an increased risk of chronic obstructive pulmonary disease (COPD) in mid-adulthood. In this review, we position moderate to late preterm birth within the framework of prematurity-associated lung disease (PLD), present contemporary estimates of expiratory airflow via meta-analysis, and outline priorities for mechanistic, interventional and translational research in this large gestational group.