The aim of this study was to investigate the effects of antenatal steroid treatment and/or postnatal surfactant replacement therapy on the incidence and extent of selected histopathological. findings. Seventy complete autopsies were reviewed, and only lung tissues were examined and graded. Infants were divided into treatment and control groups as follows: group 1: surfactant-treated infants (n = 15); group 2: infants whose mothers were given steroid treatment (n = 16); group 3: surfactant-treated infants whose mothers were given steroid treatment (n = 10). The control group included 29 patients not treated with surfactant and steroid. The overall incidence and severity of hyaline membrane and pulmonary hemorrhage were similar in each treatment group when compared to the control group. However, when the treatment groups were compared with each other, the incidence of severe hyaline membrane was more common in group I than in group 3. A significant reduction in severe hyaline membrane was associated with combined surfactant and antenatal steroid therapy. However, the cause for the similar incidence of selected histopathological findings in the treatment groups and the control group may be linked to oxygen toxicity due to insufficient antioxidant capacity in premature infants and barotrauma from mechanical ventilation. (C) 2008 Elsevier GmbH. All rights reserved.