 Pre- and postnatal exposure of the developing lung to inflammation is central to the development of BPD and the pulmonary inflammatory response in preterms at risk of developing BPD is established very early in life. Corticosteroids have antiinflammatory properties and early inhalation of corticosteroids may allow for beneficial local effects on the pulmonary system prior to the development of a full inflammatory response with a lower risk of undesirable systemic side effects. 