Diagnostic Utility of Pathological Investigations in Late Gestation Stillbirth: A Cohort Study

Objective Near term unexpected stillbirth is a common, complex diagnostic challenge. We review a large cohort of near term to term gestation unexpected fetal deaths to document the common patterns of pathology and evaluate the utility of various standard autopsy procedures. Methods A total of 123 perinatal autopsies consisting of 94 intrauterine fetal deaths (IUFDs) and 29 intrapartum deaths (IPDs) were reviewed. Deaths were classified according to the laboratory investigations establishing cause of death. Results Cause of death was attributable to placental pathology without autopsy in 55.3% of IUFD and 17% of IPD. Correlative findings at autopsy increased the ability to establish cause of death in 86.2% of IUFD and 62% of IPD. Histology was largely corroborative, with the brain, lungs, and heart demonstrating significant changes in 46%, 34.5%, and 13.8%, respectively. Microbiology was corroborative but demonstrated single organism growth in 6 of 29 cases of fatal acute chorioamnionitis. Newborn metabolic screening revealed only elevated thyroid-stimulating hormone levels in 3 cases, of questionable relevance. Aneuploidy was established by screening molecular studies in 5 IUFDs, all of which had external or visceral dysmorphism. Karyotype was established in 69 cases and was not contributory in any of the IPD: 3 IUFDs had changes of unknown significance. Cause of death was not established at autopsy in 9% of IUFD and 10% of IPD. Discussion This is the largest uniformly investigated cohort of late gestation unexpected fetal deaths studied. We confirm the importance of both placental and fetal autopsy in establishing cause of death. Autopsy histology, microbiology, and cytogenetics provide important but largely corroborative data.