Perinatal Pulmonary Hemorrhage: A Retrospective Autopsy Case Series.

Perinatal pulmonary hemorrhage (PH) is a condition characterized by blood loss via the respiratory tract with an approximate incidence of 0.1% in all newborns. The histologic characteristics of the lung in PH are not well characterized, and we hypothesized that pulmonary maldevelopment such as pulmonary hypoplasia may contribute to PH. In addition, we sought to find any correlations with placental pathology. Retrospective study of fetal and neonatal autopsies with diagnosis of PH was performed between the years from 2009 to 2015. Autopsy reports, placental pathology reports, and hematoxylin and eosin sections of the lung were reviewed. Of the 17 cases which were identified meeting inclusion criteria, PH ranged from mild (<5% in each lung) to severe (>75% in both lungs). PH involved >50% of both lungs in 6 cases. Pulmonary hypoplasia was designated in 7 of 17 (41.17%) cases with PH. Pulmonary hypoplasia and/or persistence of intra-acinar arterioles was seen in 13 of 17 (76.4%) cases. No specific placental pathology was seen universally in the cases of PH, but either maternal or fetal vascular malperfusion was noted in 14 of 17 (82%) cases. Our data suggest a high prevalence of pulmonary maldevelopment, such as pulmonary hypoplasia and persistence of intra-acinar arterioles, in cases with PH. Although no specific placental pathology is seen in PH, maternal and fetal vascular pathology is common.