EN
In the introduction of the paper essential physiologic factors to sustain the gestation in sows were presented as well as the mechanism of parturition. It was added that every deviation of this situation may lead to the interruption of gestation and death of the embryos or fetuses, respectively. The main topic of this review of literature are viral infections during gestation of the sows being the most often occurring causes of reproductive failure in swine. In connection with this kind of etiology the pathogenicity of the essential viral species was characterized in causing: embryonic or fetal death, return to estrus, abortion, early or late farrowing, birth of mummies, weak and stillborn piglets. Two ways of reaching the embryo or fetus were indicated, causing: the indirect reproductive failure or the direct reproductive failure. In the first case the main reason is a general viral infection, for example swine influenza. In the second possibility the viral agent has an affinity to the reproductive tract and embryos or fetuses. The following viruses causing directly reproductive problems were mentioned, being: PRRSV, CSFV, PEV, EMCV, PCV2 and ADV, with indication of the highest importance of PRRSV, PCV2 and PPV. Clinical symptoms, reproductive manifestation, fetal pathological changes and diagnostic tests in relation to the discussed viral diseases of reproduction in swine were presented.