A premature newborn baby is any newborn born before the 37^th gestation week. According to their gestational age at birth, premature newborn babies are divided into extreme premature babies (< 28 week), very early premature babies (28-32 week), early premature babes (32-36 week) and late premature babies (> 36 week). Premature birth leads to disruption and alterations in the structure and function of the respiratory system as well as of the pulmonary and systemic immunity. The lung parenchyma is immature at birth because alveolarization begins at 36-37 week and continues until the eighth year of life (Figure 1).³ Compromised development of pulmonary acini resulting in the creation of larger and fewer alveoli with thinned alveolar-capillary membranes and altered capillary vascularization directly leads to reduced respiratory ventilation and perfusion.³⁶ This leaves repercussions not only in this period of life but also further on as a manifested reduced lung capacity for gas exchange.³⁷

Despite initial assumptions that pulmonary hypoplasia and small immature airways are a predisposing factor, multifactorial influence is a determining factor in the development of chronic obstructive disease and asthma. Numerous factors from the environment (cigarette smoke, air pollution), genetic predisposition to atopy or asthma, susceptibility to severe respiratory viral infections (RSV, HRV), alterations in the microbiome and  in the immature immune system each contribute in their own way to the development of asthma in premature infants. Understanding why these preterm infants are at higher risk of developing asthma is crucial for further prevention, early detection and possibly delaying the onset of asthma, all in order to reduce the increased morbidity and mortality in this group of patients.¹

On the other hand, improved intensive neonatal care over recent years has contributed to increased survival even of extremely premature newborns in whom the severity of the initial lung affectedness is more serious and of a larger scale, which directly leads to an increase in the number of children with BPD and chronic respiratory problems further in their lives.²

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Emilija Manasievski

PHI University Clinic for Respiratory Diseases in Children - Kozle, Skopje, Republic of North Macedonia