PREVALENCE OF CONGENITAL MALFORMATIONS AND SPONTANEOUS MISCARRIAGES IN POPULATIONS WITH DIFFERENT GENETIC AND DEMOGRAPHIC STRUCTURE

Abstract

The article presents the results of studing the dynamics of some genetic and demographic indicators of the regional populations of the Kherson region (the level of interethnic and homolocal mono-ethnic Ukrainian marriages, the endogamy index) during the past 56 years and its influence on the prevalence of congenital malformations and spontaneous miscarriages. The prevalence of congenital malformations in the population correlates with the prevalence of spontaneous miscarriages (r = -0.52±0.12; t_r = 2.4 > t₀₅ = 2.12) that indicates the presence of a “screening” selection process that eliminates non-viable genotypes in the embryonic period of ontogenesis. The areas in which there has been a significant increase in the share of interethnic marriages over the years of study are characterized by higher mean prevalence rates of congenital malformations (r = 0.50±0.46, t_r = 2.3 > t₀₅ = 2.12) and a low frequency of reproductive losses r = -0.27±0.24, t_r = 1.13 < t₀₅ = 2.12). In regions where there was a reduction in the number of mono-ethnic marriages (an average of 71.2 to 62.9 %), the prevalence of congenital malformations of newborns and reproductive losses (26.0±4.1 and 41.4±6.5 respectively) exceeded the average regional indicators (21.7±3.9 and 36.3±5.9 ‰). The areas that now represent elementary populations (endogamy index 0.5 and above) and in which the proportion of homo-local mono-ethnic Ukrainian marriages is increasing or relatively constant, are characterized by lower average prevalence rates of congenital malformations of newborns (19.3±3.0, respectively ‰ and 17,7±3,4 ‰) in comparison with the populations in which the share of such marriages decreased significantly with time (28.1±4.4) ‰. The frequency of homolocal Ukrainian marriages correlates with the incidence of congenital malformations (r = -0.37±0.23; t_r = 1.59 < t₀₅ = 2.12), although this relationship is not statistically significant. Correlation analysis also showed a weak positive correlation between the current indicators of the level of endogamous monoethnic Ukrainian marriages and the prevalence of spontaneous abortions in populations (r = 0.25 ± 0.24, t_r = 1.0 < t₀₅ = 2.12), which indicates possible influence of the genetic drift on the frequency of reproductive losses. The level of endogamy does not significantly affect the prevalence of malformations (r = -0.20±0.24, t_r = 0.8 < t₀₅ = 2.12). When analyzing the prevalence and structure of congenital and hereditary pathology, the effect of population-genetic and genetic-demographic factors should be taken into account. Investigation of the intensity and direction of population transformations in time should include studying the influence of the triune aspects of their dynamics: micro­evolution factors, genetic and demographic changes, epidemiology of hereditary and congenital pathology.