Morphogenesis of decidual transformation of the endometrium. A literature review

Decidual transformation of the endometrium is the final stage of the cyclic endometrial transformation during pregnancy. The morphogenesis of endometrial transformation is represented by clearly coordinated hormone-receptor interactions via immunological, angiogenic, and apoptotic factors that are necessary for pregnancy development. The pathology of morphogenesis can cause implantation disorders and early reproductive losses, highlighting the medical and social relevance of this issue. The aim of this review was to analyze the literature data on the morphogenesis of endometrial transformation in the first trimester of pregnancy. Open access full-text publications from the PubMed and eLibrary databases, as well as Russian relevant journals from 1999 to 2021 were used for the analysis. The morphogenesis of endometrial transformation in the first trimester of pregnancy is determined by cyclic endometrial transformation adequacy and the optimal endometrium-embryo interaction under the influence of many factors. The complex approach in evaluation of multiple links in the morphogenesis of decidual transformation of the endometrium (steroidogenesis, immunogenesis, angiogenesis, and apoptosis) will reveal molecular mechanisms of pregnancy termination due to altered decidual membrane formation. The fundamental value of molecular mechanisms underlying endometrial transformation in understanding the pathogenesis of reproductive failures dictates the necessity of endometrial transformation investigation under conditions of reprogramming and remodeling during pregnancy.