ABSTRACT
Examination of randomly selected pregnant women of the Kharkov city showed that the structure of marriage had undergone considerable changes during two successive generations. The number of endogamous marriages decreased, the percentage of marriages between persons of different nationalities being increased, which adequately reflects social-demographic processes taking place currently in all human populations. Judging by the data obtained, these changes in percentage of exogamous marriages do not considerably influence the probability of pregnancy failure which can be accounted for disturbed foeto-maternal immunological interrelations. No correlations between immunological indices and the degree of heterozygosity in women and the structure of marriages was demonstrated. The percentage of married couples with tainted heredity (spontaneous abortions, still-birth) was considerably higher among women with habitual pregnancy failure, which may testify to a certain role of hereditary predisposition to immune failure.