Histological chorioamnionitis and respiratory outcome in preterm infants

A considerable body of human and animal experimental evidence links antenatal inflammation to both accelerated maturation and adverse development of the lung. Initial reports suggest that in preterm infants histological chorioamnionitis is associated with a decreased incidence of respiratory distress syndrome (RDS), while the incidence of bronchopulmonary dysplasia (BPD) is increased. Considerable variation exists in the findings of subsequent human studies, largely dependent on differences in inclusion and exclusion criteria. Taking these differences into account, recent studies generally seem to confirm the effect of chorioamnionitis on RDS incidence, while no effect on BPD is seen. The increased use of antenatal steroids and the diminished effects of secondary pro-inflammatory hits seem to explain part of this change. Additional research is needed to explore these complex interactions and their underlying mechanisms, and evaluate the long term pulmonary effects of antenatal inflammation.