Results: CHD was identified in 99 (13.6 %) fetuses. Most common categories were septal defects and complex anomalies. Associated anomalies were found in 67 fetuses (67.7 %). In this group, septal defects were the most common CHD, frequency being significantly higher than in the group of isolated cardiac anomalies (p=0.012). Comparison of prenatal and postmortem diagnoses (50 cases) showed complete or partial agreement in 36 and 10 cases (72 % and 20 %, respectively) and complete disagreement in 4 cases (8 %). In the latter group, prenatal diagnosis had not been done by a pediatric cardiologist. Conclusion: The high prevalence of CHD in lost pregnancies highlights the importance of systematic fetal autopsy performed by a specialized pediatric pathologist. Objective: The appearance of pathological calcification, which leads to significant changes of vascular wall, which underlie the development of atherosclerotic complications, has a great importance in the morphology of atherosclerosis development. Purpose of the work is the study of pathological biomineralization in heart valves affected by atherosclerosis. Method: The study was conducted on sectional material of mitral and aortic valves obtained during autopsy. The tissue of heart valves was studied by methods of histology, electron microscopy, X-ray diffraction, infrared spectroscopy. Results: Macroscopically mitral and aortic valves are thickened, opaque, dull whitish, sometimes with deformity and ulceration. Histology observed the formation of atherosclerotic plaques, fibrous changes, and inflammatory infiltration. According to X-ray phase analysis biominerals in heart valves are represented by apatite crystalline phase. Sizes of crystals have distinct age dependence. The results of infrared spectroscopy revealed absorption bands of carbonate apatite replacement; in all instances they correspond to the type of substitution B (CO3 2-replaces PO4 3-). Conclusion: The study of pathological mineral formations on human heart valves by the range of morphological and physicochemical methods show that they are aggregates of interacting organic and mineral components, their ratio changes with "maturation": the organic component decreases and the mineral component, represented by carbonate containing hydroxyapatite doped with chlorine grows while improving, so the process is dynamic.