ACE2 receptors finding in placenta with intrauterine fetal Covid-19 infection: a meta-analysis

Objective: Association between ACE2 receptors in the placenta and the incidence of intrauterine COVID-19 infection in pregnant women infected with COVID-19 Methods: Systematic review and meta-analysis of placenta in pregnant women with COVID-19 infection, ACE2 receptor in placenta, and RT-PCR of neonates from COVID-19 pregnant women. This study followed the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) protocol. Results: 6 journals meet the inclusion criteria. ACE2 receptors were found in syncytiotrophoblasts 72/72 (100%), cytotrophoblasts 41/72 (56.9%), extravillous trophoblasts 24/72 (33.3%), decidual cells 2/72 (2.7%), villous stromal cells 1/72 (1.3%), and 1/72 stromal cells (1.3%) with the incidence of neonates infected with SARS-CoV-2 from pregnant women with COVID-19 10.5%, odds ratio (OR) between ACE2 receptors and neonates infected with COVID-19 is 1.97 (95%CI 0.05–81.09), the pooled proportion of ACE2 receptor findings in 72 placentas in pregnant women with COVID-19 infection, syncytiotrophoblast 98.3 (95% CI 94.3–99.9), cytotrophoblast 40.3 (95% CI 2.3–88.9), and extravillous trophoblast 35.2 (95% CI 0.2–88.5). Conclusion: Expression of ACE2 receptors is always present in the placenta of pregnant women, and there is an association but non-significant between ACE2 receptors in the placenta and the incidence of COVID-19 intrauterine infection with an odds ratio of 1.97 (95%CI 0.05-81.09).