Placenta, the Key Witness of COVID-19 Infection in Premature Births.

Adverse perinatal outcomes, such as increased risks of pre-eclampsia, miscarriage, premature birth, and stillbirth have been reported in SARS-CoV-2 infection. For a better understanding of COVID-19 complications in pregnancy, histopathological changes in the placenta, which is the interface between mother and foetus, could be the place to look at. The aim of this study was to determine placental histopathological changes and their role in preterm birth in pregnant women with SARS-CoV-2 infection. We performed a prospective, observational study in a COVID-only hospital, which included 39 pregnant women with SARS-CoV-2 infection and preterm birth compared with a control group of 39 women COVID-19 negative with preterm birth and a placental pathology exam available. The microscopic examination of all placentas revealed placental infarction (64.1% vs. 30.8%), decidual arteriopathy (66.7% vs. 23.1%), intervillous thrombi (53.8% vs. 38.5%), perivillous fibrin deposits (59% vs. 46.2%), inflammatory infiltrate (69.2% vs. 46.2%), chorangiosis (17.9% vs. 10.3%), and accelerated maturation of the villi (23.1% vs. 28.2%).