Fig. 1.

Potential mechanisms factors influencing SARS-CoV-2 in utero (transplacental) transmission. Maternal viremia, disruption of placental barrier and presence of receptors in fetal and placental tissue (red boxes) should occur simultaneously for in-utero transmission to occur. The presence of angiotensin converting enzyme 2 (ACE2) receptors in fetal tissue and co-existence of transmembrane serine protease 2 (TMPRSS2) receptor that can prime the spike protein in the fetal tissue is necessary to enable viral fusion with fetal tissues. Copyright Satyan Lakshminrusimha.