 Per day, approximately 10 patients undergo routine registration for delivery at our department. All of them will be assessed for eligibility for the study. Approximately 60 of these patients will present with a normal vaginal flora without infection, which would lead to the number of 610 potentially eligible patients per day. A systematic review on the prevalence of maternal GBS colonization in Europe reported rates ranging from 6.5 to 36. The carriage rates varied with Eastern Europe 19.7 to 29.3, Western Europe 11 to 21, Scandinavia 24.3 to 36, and Southern Europe 6.5 to 32 17. The investigators therefore conclude that the GBS colonization rates within our obstetric population will be approximately 25. This will lead to the number of 1.56 potentially eligible patients per day, who could then be assigned to randomization. 