text: Role of ACE2 in pregnancy and potential implications for COVID 19 susceptibility In times of coronavirus disease 2019 COVID 19 the impact of severe acute respiratory syndrome SARS coronavirus CoV 2 infection on pregnancy is still unclear The presence of angiotensin converting enzyme ACE 2 ACE2 the main receptor for SARS CoV 2 in human placentas indicates that this organ can be vulnerable for viral infection during pregnancy However for this to happen additional molecular processes are critical to allow viral entry in cells its replication and disease manifestation particularly in the placenta and or feto maternal circulation Beyond the risk of vertical transmission COVID 19 is also proposed to deplete ACE2 protein and its biological actions in the placenta It is postulated that such effects may impair essential processes during placentation and maternal hemodynamic adaptations in COVID 19 pregnancy features also observed in several disorders of pregnancy This review gathers information indicating risks and protective features related to ACE2 changes in COVID 19 pregnancies First we describe the mechanisms of SARS CoV 2 infection having ACE2 as a main entry door and current evidence of viral infection in the placenta Further we discuss the central role of ACE2 in physiological systems such as the renin angiotensin system RAS and the kallikrein kinin system KKS both active during placentation and hemodynamic adaptations of pregnancy Significant knowledge gaps are also identified and should be urgently filled to better understand the fate of ACE2 in COVID 19 pregnancies and the potential associated risks Emerging knowledge will be able to improve the early stratification of high risk pregnancies with COVID 19 exposure as well as to guide better management and follow up of these mothers and their children 