SARS-CoV-2 Placentitis with Intraparenchymal Thrombohematomas: Association with Intrauterine Fetal Demise, Perinatal Morbidity, and Ultrasonographic Findings

ABSTRACT

Background: SARS-CoV-2 placentitis is defined by the triad of histiocytic or mixed inflammatory intervillositis, increased perivillous fibrin deposition, and villous trophoblastic necrosis. We have observed multiple cases of intrauterine fetal demise (IUFD) or perinatal morbidity with intraparenchymal thrombohematomas, a feature not previously linked to poor outcomes associated with SARS-CoV-2-placentitis. Here we present 17 cases with such findings and provide a possible point of intervention as these lesions can be identified by ultrasonography. Design: A retrospective study, approved by the Institutional Review Board, was performed by searching the terms SARS-CoV-2 placentitis or SARS-CoV-2 infection or COVID in our pathology database for all in-house deliveries and cases from the consult practice of the authors between 1/1/21 and 9/24/21. Clinical data was obtained via the electronic medical records or through contacting the consulting pathologists. Results: Twenty-three cases were retrieved and reviewed for the presence of thrombohematomas in the maternal space. Seventeen cases had thrombohematomas, intervillous thrombi, or intervillous hemorrhage in addition to classic SARS-CoV-2 placentitis, and 12 of those cases (71%) were associated with IUFD. The period between a positive maternal COVID test and loss was less than 14 days in all but three cases of IUFD (75%). The non-IUFD cases were all associated with other perinatal morbidity. In 8 of 17 cases (47%), thrombohematomas were noted grossly. The presence of multiple placental lakes were identified in three cases where placental imaging was available. Representative gross and histologic findings and an ultrasound displaying placental lakes are presented in Figures 1 and 2, respectively. Clinical data associated with each case is in Table 1. Conclusions: We identify a novel feature present in placentas with SARS-CoV-2 placentitis associated with poor outcomes. The often grossly identifiable thrombohematomas were present in 17 cases of SARS-CoV-2 placentitis, the majority of which were associated with IUFD, suggesting that their presence is a marker for increased perinatal morbidity and mortality. We also show that these thrombohematomas can be identified by ultrasound, demonstrating that imaging the placenta is critical in pregnancies affected by COVID-19 independent of maternal symptoms as it may identify markers of severe placental damage that can be associated with IUFD or significant perinatal morbidity.