[Comparative evaluation of the incidence of premature labor among female workers in plants with different work profiles].
The incidence rate of premature births has been studied in 777 women employed at a chemical plant, 1430 women working in clothing industry, and 805 port women-workers. In the mentioned groups 35,41 and women, respectively, had undergone premature births. This constituted 4.5, 2.87 and 3.85%. However, in women who had delivered, these percentages have gone up to 5.55, 4.18 and 5.24. With reference to the first as well as the second findings the above differences are statistically insignificant. In the test plants no workplaces exposing to a greater risk manifested by frequent premature births have been disclosed. In all the three plants the first premature birth was recorded almost at the same rate in women who previously had no pregnancy or delivered on time, while the subsequent premature births and most frequently been directly preceded by a premature delivery. Spontaneous abortion preceded the premature births over five, and the pregnancy interruption procedure over six times less frequently than the normal parturition. The direct and most often conjectural causes of premature births mentioned by the examined subjects include: premature flow of the amniotic fluid, physical effort disconnected with the work performed, serological incompatibility involving Rh factor, psychic trauma and gestosis.