Using computer analysis the authors studied the relationship between the various clinical forms of urinary tract infections and premature deliveries, i.e. dysmaturity in a population including several thousands of individuals. In the frameworks of uniform and monitored perinatal obstetric and neonatologic care system--the uniform diagnostics of bacteriuria was established. The standard birth-weights for the regions involved by our care were calculated, too. The basic observations of Kass were still found to be valid. In case of urinary tract infections, an increased rate of premature deliveries with respect to both birth-weights and gestational age of pregnancy should be reckoned with. Computer analysis proved not only a tendency for premature deliveries but also retarded intrauterine growth of the foetus.