Rationale. Endocrinopathy, such as thyroid pathology, can underlie premature aging, including in patients with reproductive disturbances. Aim. The study aimed to provide biological grounds for the concept of premature aging in patients with uterine endothelial dysfunction as a sign of premature aging in cases of hypothyroidism. Materials and Methods. The study included 60 pregnant women (with euthyroidism – 25; hypothyroidism — 25 (15 — autoimmune thyroiditis, 10 — polyglandular syndrome). The authors conducted clinical and pathomorphological tests of the uterine (light-optical, atomic-powered and raster electron microscopy with a detector for the study of elementoses (oxygen)). Results and Discussion. The changes in the uterus were observed in the myometrium vessels and progressed in the following order: euthyroid state, hypothyroidism. Some of the changes were typical for menopausal alteration in this organ: the appearance of connective tissue and atrophic changes, which was primarily observed in patients with hypothyroidism. Vascular wall sclerosis was revealed as well as destructive changes in the endothelium and even fragmentary necrosis in some cases. This led to the thrombosis in the vasculature along with anomalies in erythrocyte structure, their hemolysis, and proneness to sludge. Indirectly, it became a pathogenetic factor of a decrease in the content of oxygen in the uterine vessels, which was a sign of premature aging, influenced the homeostasis of the fetus leading to its viability impairments.