Evidence of vertical transmission of SARS-CoV-2 and interstitial pneumonia in second trimester twin stillbirth in asymptomatic woman. Case report and review of the literature

: Data on the vertical transmission rate of COVID-19 in pregnancy are limited, while data reporting mother-fetal transmission in the second trimester of pregnancy are controversial. We described a case of second trimester twin stillbirth in a woman positive for SARS-CoV-2 in which, despite the absence of respiratory syndrome, placental and fetal markers of infection were detected. The patient developed a clinical chorioamnionitis and spontaneously delivered two stillborn infants. Placental histology and immunohistochemistry demonstrated SARS-CoV-2 infection mostly within the syncytiotrophoblast and the fetal autopsy showed development of interstitial pneumonia. Our findings demonstrate that, in utero vertical transmission is possible, also in asymptomatic SARS-CoV-2 pregnant women and that infection can lead to severe morbidity in the second trimester of pregnancy.