Histologic correlates of viral and bacterial infection of the placenta associated with severe morbidity and mortality in the newborn

The purpose of this study was to correlate the histologic features of the placenta with the in situ detection of viral or bacterial nucleic acids in cases of severe morbidity and mortality in the neonatal period. The criteria for the cases were either fetal or neonatal death (11 cases with autopsy material available in 8 cases) or idiopathic severe respiratory distress or central nervous system-related symptoms at birth (49 cases). Controls included 11 placentas from births with no morbidity and 6 placentas that were associated with severe neonatal morbidity of known etiology (trisomy, ruptured uterus, prolapsed cord). The 77 placental tissues were analyzed with a consensus bacterial probe and for a wide variety of viral infections. An infectious cause was found in 46/60 (76%) of cases; these were distributed as follows: enterovirus, 23 cases (22 were coxsackie virus); bacterial (consensus probe), 15 cases; cytomegalovirus (CMV), 4 cases; herpes simplex virus (HSV), 2 cases; parvovirus, 2 cases. The infectious agents localized primarily to Hofbauer cells and trophoblasts. In each of the 8 cases for which autopsy material was available, the same infectious agent that was detected in the placenta was also detected in the autopsy material (spleen, heart, central nervous system, or lungs). No infectious agent was detected in any of the 17 controls. Viral inclusions (only evident for DNA viruses) and stem vessel vasculitis were the 2 histologic findings that were associated with infectious disease in the placenta (P = 0.025). These data show that infection of the villi is highly associated with neonatal morbidity and mortality and that the histologic findings are, in most cases, nonspecific for infection.