In human populations natural selection is shifting to the side of prenatal development and appears as negative outcomes of pregnancies such as spontaneous abortions, ectopic pregnancies and stillbirths. Therefore, it is important to study dynamics of changes in reproductive characteristics and selection indexes of the populations in order to predict possible problems and numbers of genetic burden in the populations. Ukraine is poorly studied in this area. The aim of the study was to investigate indicators which characterize the population structure of Lutsk city, the intensity of natural selection, migration and their dynamics in two generations. 583 post-reproductive age females were anonymously questioned. Age, places of birth of the couple, the number of pregnancies and their outcomes were considered. Results show that natural selection indexes (Crow’s indexes) are decreasing from the first generation (0,26) to the second (0,20). Migration coefficients in the population of Lutsk decreased from 0.89 to 0.82 per generation and show intensive urbanization of the city for the studied time. The efficiency of the migration is low, since the biggest number of migrants come from the villages of the Volyn region (45% for first generations and 64% for the second one), or adjacent regions of Ukraine (35% and 27%, respectively). The population of Lutsk has a narrowed type of reproduction, where average number of offspring per female equal 1,86 for the first generation and 1,73 for the second generation.

Aim. Due to the fact that women's reproductive behavior has been changing with the development of civilization, from natural uncontrolled fertility in the early stages of human development to reproductive technologies in our time, the aim of this work was to study the direction and intensity of natural selection index and changes of the quantitative characteristics of reproduction in women residents of Kharkiv in three successive generations. Methods. Material was collected in 1990 and 2017. The obstetric and gynecological history of the inhabitants of Kharkiv was studied. The first generation included 589 women who were born in 1900–1925, 244 women born in the period 1928–1955, made up the second generation, 288 women who were born in 1956–1979, were assigned to third generation. Results. The total selection index is reduced from 0.56 in the first generation to 0.29 and 0.28 in the second and third generations, respectively. Over the eighty-year period, the differential fertility rate has decreased. The percentage of women with pathological pregnancies increased from 4.9 in the first generation, to 22.5 in the second and 18.4 in the third generation. Conclusions. The total selection index in the Kharkiv population into three successive generations has decreased by half: from 0.56 to 0.28, the index of differential mortality has decreased by almost four times. Keywords: reproductive characteristics, Kharkov population, Crow's index, selection, generations.

Aim. According to the data characterizing reproductive behavior of women, assess an impact of ethnicity and level of education on the intensity of selection in the urbanized multinational population of Kharkiv city. Methods. Data from obstetric history of 532 post-reproductive age women was studied. Results. For indicators of the number of pregnancies with favorable and unfavorable outcomes, universally valid statistical indicators were calculated. Crow’s indexes were calculated as indicators of the intensity of selection. The total selection index for Ukrainians living in Kharkiv equal 0.26, for Russians it is 0.32, and for the group formed from representatives of rare nationalities this index is 0.75. In a group of women with secondary education total selection index is 0.26, in a group with highest education it is 0.35. Conclusions. Ethnicity and level of education of women affects reproductive behavior and determine number of pregnancies and their outcomes. Selection indexes differ in ethnic groups and in groups with different levels of education. Keywords: reproductive characteristics, Kharkiv population, Crow's index, selection, nationality, education.

Aim. Reproductive behavior of women has particular importance in the reproduction of the population and depends on cultural characteristics and religious views. Number of birth and medical abortions become artificially regulated; nevertheless selection in human populations does not disappear. Therefore, the aim of this task to study the direction and intensity of indexes of natural selection and the dynamics of the gene pool in the Kharkiv population for two adjacent generations. Methods. The material was collected in 2017. Anonymous questionnaires were conducted for women in postreproductive age. The questionnaire includes questions which reflect a woman's gynecological and obstetrical anamnesis. The number of pregnancies and their outcomes was calculated: medical and spontaneous abortions, ectopic pregnancies, number of stillbirths and live births. Results. In one generation, the total selection index decrease from 0.29 to 0.28, while the differential fertility index is much higher than the differential mortality index. The average number of pregnancies and medical abortions reduced in the younger generation with statistically significant difference. Conclusions. The Kharkov population is characterized by a narrow type of reproduction. The dynamics of Crow's indexes are in line with global trends. From the older generation to the younger the total selection index decreases gradually.Keywords: reproductive characteristics,Kharkov population, Crow's index, selection, generations.