Respiratory consequences of late preterm birth

Abstract

In developed countries most preterm births occur between 34 and 37 weeks' gestation. Deliveries during this 'late preterm' period are increasing and, since even mild prematurity is now recognised to be associated with adverse health outcomes, this presents healthcare challenges. Respiratory problems associated with late preterm birth include neonatal respiratory distress, severe RSV infection and childhood wheezing. Late preterm birth prematurely interrupts in utero lung development and is associated with maternal and early life factors which adversely affect the developing respiratory system. This review considers 1) mechanisms underlying the association between late preterm birth and impaired respiratory development, 2) respiratory morbidity associated with late preterm birth, particularly long-term outcomes, and 3) interventions which might protect respiratory development by addressing risk factors affecting the late preterm population, including maternal smoking, early life growth restriction and vulnerability to viral infection.

Hospital admissions for lower respiratory tract infections in children born moderately/late preterm

“…This causes inadequate maintenance of functional residual capacity, decreased compliance, and smaller airway diameters compared to term infants. Together with an infection early in the course of immune maturation causing a greater inflammatory response, these features make MP and LP infants susceptible to more severe symptoms of LRTIs …”

“…Moderately preterm (MP, born at 32 +0 to 33 +6 weeks) and late preterm (LP, born at 34 +0 to 36 +6 weeks) infants account for over 80% of all preterm births . These infants have an increased risk of early‐childhood as well as later respiratory morbidity, such as asthma . Lower respiratory tract infections (LRTIs) are the leading cause of hospitalization in preschool children .…”

Effect of late preterm birth on lung clearance index and respiratory physiology in school‐age children

“…The last 6 weeks of gestation represent a critical period of growth and development of the fetal lungs . Prenatal factors, more common in LP infants, such as maternal smoking, hypertension, diabetes, and pre‐eclampsia, increase the risk of placental insufficiency and in utero growth restriction which, in turn, might be associated with persistently impaired respiratory development . Additionally, LP infants are susceptible to lower respiratory tract infections, especially respiratory syncytial virus, as a consequence of immature humoral immunity .…”

“…Prenatal factors, more common in LP infants, such as maternal smoking, hypertension, diabetes, and pre‐eclampsia, increase the risk of placental insufficiency and in utero growth restriction which, in turn, might be associated with persistently impaired respiratory development . Additionally, LP infants are susceptible to lower respiratory tract infections, especially respiratory syncytial virus, as a consequence of immature humoral immunity . The combination of early respiratory infections affecting a previously compromised lung of the LP infant may have short‐ and even long‐term effects on respiratory function, such as an increased risk of COPD in adult life …”

Asthma and atopic dermatitis after early‐, late‐, and post‐term birth

“…Children born prematurely appear to carry an increased risk of asthma and/or asthma‐like symptoms in childhood, whereas their risk of atopic dermatitis has been found to be decreased compared with children born at a later gestational age (GA).…”