Vertical Transmission of SARS-CoV-2 (COVID-19): Are Hypotheses More than Evidences?

In spite of the increasing, accumulating knowledge on the novel pandemic coronavirus severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), questions on the coronavirus disease-2019 (COVID-19) infection transmission from mothers to fetuses or neonates during pregnancy and peripartum period remain pending and have not been addressed so far. SARS-CoV-2, a RNA single-stranded virus, has been detected in the amniotic fluid, in the cord blood and in the placentas of the infected women. In the light of these findings, the theoretical risk of intrauterine infection for fetuses, or of peripartum infection occurring during delivery for neonates, has a biological plausibility. The extent of this putative risk might, however, vary during the different stages of pregnancy, owing to several variables (physiological modifications of the placenta, virus receptors' expression, or delivery route). This brief review provides an overview of the current evidence in this area. Further data, based on national and international multicenter registries, are needed not only to clearly assess the extent of the risk for vertical transmission, but also to ultimately establish solid guidelines and consistent recommendations.