ABSTRACT
INTRODUCTION: COVID-19, the disease caused by the novel coronavirus SARS-CoV-2, is a severe systemic thrombotic syndrome that emerged in 2019, with an ensuing pandemic. To evaluate the impact of this disease on placental tissue and perinatal outcome, histological, immunohistochemical and ultrastructural analyses of placental tissue were performed for five cases of pregnant women with COVID-19. CASE REPORTS: All five pregnant women in this series developed COVID-19 in late pregnancy. Two patients experienced respiratory distress, and computed tomography revealed signs of pneumonia, with bilateral involvement, multiple lobular and subsegmental areas of consolidation and ground-glass opacities. Histological studies of placental tissue revealed the presence of slight signs of maternal vascular underperfusion (MVUs) or foetal vascular underperfusion (FVUs) lesions and mild inflammatory lesions. CD15 immunoreactivity in the placental tissue was low in all cases, demonstrating that in these cases there was not severe foetal hypoxia/asphyxia risk for newborns or distal vascular immaturity. In all cases examined, ultrastructural analyses showed spherical-like coronavirus particles with an electron intermediate-density core as well as projections from the surface as spike-like structures in the syncytiotrophoblasts. At term, all of the women delivered newborns who were negative for SARS-CoV-2 by nasopharyngeal testing in their first day of life. All newborns were exclusively breastfed and were discharged on the 3rd day of life. CONCLUSIONS: In conclusion, placental patterns in pregnancy due to COVID-19 in the late stage of gestation indicate no evidence of vertical trans-placental SARS-CoV-2 transmission or a significant impact on the perinatal outcome of newborns, in both mild and more severe cases.