The histologic evolution of revealed, acute abruptions.

There is considerable interest in using pathology to confirm acute abruptions. It has been suggested that pathologic findings can help to determine the timing of abruptions. Because of the dearth of evidence in the literature supporting this claim and its medicolegal implications, we undertook this study to explore further the possibility of timing abruptions by histopathology. We sought to correlate bleeding interval (duration from maternal presentation with vaginal bleeding [revealed abruption] to placental delivery) with placental histopathologic findings. We performed a retrospective review of clinical data and placental pathology from all cases of clinically diagnosed, acute, revealed abruptions at a single, large institution in New England between 2000 and 2015. Cases were identified based on clinical diagnoses, bleeding intervals were calculated from clinical notes, and histologic evaluations were performed by 2 pathologists blinded to the bleeding intervals. A total of 177 cases were analyzed. Of these, 103 (58%) had histologic findings corroborating the clinical diagnosis of abruption. The most frequent finding was maternal surface indentation (51 cases) followed by intravillous hemorrhage (50 cases). The former was also the earliest finding, with a minimum bleeding interval of 4 minutes. In multivariate modeling, plasma cell deciduitis was significantly associated with a longer bleeding interval (median 63 hours). If there were 2 pathologic findings, there was a trend toward a longer bleeding interval. There was modest sensitivity for the pathologic diagnosis of acute revealed abruption. Although there was not a clear, stepwise progression of histologic lesions; the presence of 2 or more findings tended to be seen with longer bleeding intervals. Our results suggest that histologic findings cannot be used to time acute revealed abruptions reliably, and any interpretation of such should be made with caution.