Histologic and Immunohistochemical Evaluation of 65 Placentas from Women with Polymerase Chain Reaction-proven Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection.

Levitan, Daniel; London, Viktoriya; McLaren, Rodney A; Mann, Justin David; Cheng, Ke; Silver, Michael; Balhotra, Kimen Singh; McCalla, Sandra; Loukeris, Kristina

CONTEXT -Coronavirus disease 2019 (COVID-19) has been shown to have effects outside of the respiratory system. Placental pathology in the setting of maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection remains a topic of great interest as earlier studies have shown mixed results. OBJECTIVE -To ascertain whether maternal SARS-CoV-2 infection is associated with any specific placental histopathology, and to evaluate the virus's propensity for direct placental involvement. DESIGN -Placentas from 65 women with polymerase chain reaction-proven SARS-CoV-2 infection underwent histologic evaluation using Amsterdam consensus group criteria and terminology. Another 85 placentas from women without SARS-CoV-2 constituted the negative control group. Sixty-four of the placentas from the SARS-CoV-2-positive group underwent immunohistochemical staining for SARS-CoV-2 nucleocapsid protein. RESULTS -Pathologic findings were divided into maternal vascular malperfusion, fetal vascular malperfusion, chronic inflammatory lesions, amniotic fluid infection sequence, increased perivillous fibrin, intervillous thrombi, increased subchorionic fibrin, meconium-laden macrophages within fetal membranes, and chorangiosis. There was no statistically significant difference in prevalence of any specific placental histopathology between the SARS-CoV-2-positive and negative groups. There was no immunohistochemical evidence of SARS-CoV-2 virus in any of the 64 placentas that underwent staining for viral nucleocapsid protein. CONCLUSIONS -Our study results and a literature review suggest that there is no characteristic histopathology in the majority of placentas from women with SARS-CoV-2 infection. Likewise, direct placental involvement by SARS-CoV-2 is a rare event.