Objective. By retrospective data analysis of the Laboratory of the sexual system diagnostic to estimate the incidence of infections caused by BHSB in the female sex system of pregnant women and non-pregnant women in Splitsko-dalmatinska county and to show features, frequency, clinical picture, microbiological tests and treatment of infection in women and infants caused by β-hemolytic streptococci of group B and to point possible ways of preventing infection, as well as preventing the transfer of the bacterium from the mother to the newborn and the tasks of midwife of education and nursing woman in labor and newborn who are colonized by BHSB. Examines and methods. During 2017, 12 858 wipes from the female sex system were taken by routine processing in the laboratory. The BHSB screening sample is taken by all pregnant women between the weeks 35 and 37 of pregnancy by cultivating vaginal swabs and/or anorectas. The pregnant women who were positive, were treated with corresponding antibiotic. Results. Out of a total of 12 858 tested samples in 2017, 1 171 (9.1%) were positive for BHSB. Out of the total number (3 507) of pregnant women tested in the last trimester of pregnancy, 489 (13.9%) were positive at BHSB while out of the total number (9 351) of other tested women, 682 (7.3%) were positive at BHSB. Conclusion. There is a significant difference between the BHSB positive pregnant women in the last trimester of pregnancy, 13.9% (489 / 3.507) compared to the other women tested for bacterial scans of the female sexual system, 7.3% (682 / 9.351); p <0.05. Routine cervical occlusion in the third trimester of pregnancy in asymptomatic pregnant women would result in increased antenatal costs and increased probability of developing bacterial resistance due to high antibiotic use, but on the other hand there is a possibility to reduce the incidence of perinatal infections.