Pathological immune complexes (PIC) are revealed in high percent (100%) of cases by placental immunomorphological studies in insulin-dependent tissue. This leads to the development of an immunopathological process in the placental tissue. Parallel electron microscopy shows that some placental vessels are in close contact with the basal membrane of syncytiotrophoblast. PIC deposition in the area of confluence of the basal membranes of a syncytiotrophoblast and the vascular endothelium, which act as filters, results in the destruction of the basal membranes to rupture formation, causing the transplacental transport of substances together with immune complexes in the form of endocytotic vacuoles from the intervillous lacuna directly to the vessel. Active proliferation of vascular endotheliocyes leads to typical angiopathy as the body's defense reaction.