Placenta in SARS-CoV-2 infection: a new target for inflammatory and thrombotic events

Infection by SARS-CoV-2 has been shown to involve a wide range of organs and tissues, leading to a kaleidoscope of clinical conditions. Within this spectrum, an increased rate of preterm deliveries has been reported in women with COVID-19. High expression of proteins (ACE2/TMPRSS2) required for SARS- CoV-2 cell entry has been observed in the maternal-fetal tissues, supporting the possibility of placental viral involvement. A consecutive series of 6 placentas, delivered by 5 women with COVID-19 have been investigated. Three out of six placentas showed changes consistent with chronic villitis, while in one case chronic histiocytic intervillositis was diagnosed. Vascular abnormalities consisting of thrombo- hemorrhagic alterations were identified in the three cases with chronic villitis. These pathological findings: i) provide a basis to explain the higher rate of obstetric complications in these patients; 2) suggest the need to investigate heparin use in COVID-19 affected pregnant patients to prevent adverse outcomes.