Comparison of morphological changes in placenta in the conditions of physiological pregnancy and pregnancy complicated acute asphyxia in farrow with deadborn piglets was realized in the conditions of the Republic of Belarus. There were realized complex clinical and morphological studies of placenta of pregnant sows. The experimental group was formed by pegnant sows with intranatally dead fetus because of acute asphyxia in course of farrowing caused by abnormality in placental circulation(prolapse of funis or loop of cord). The second (control) group consisted of healthy bred sows with physiological farrowing and alive newborn piglets. The groups were comparable to age, number of farrowings (no more two) and housing conditions. Detailed macrographic examinations of placenta (form, size, square, weight, volume, fetus-plecentary coefficient, amnion status and so on) and cord were realized. The research result showed that in the conditions of a complicated pregnancy in the thickness index placenta there were visualized a lot of connective tissue changed locus, infarcts as well as areas, and changes in morphometric indexes. All mentioned above factors proved to be a morphological substrate of fetoplacental insufficiency, which subsequently caused asphyxia, hypoxia, small-for-gestational-age fetus, and dead birth