The investigators plan to enroll the first patient at OUH February 2013. HH and HSWJ will follow with a couple of months delay. The inclusion period is scheduled to last until the investigators have 2844 participants, who have answered the questionnaire. The investigators expect to complete the inclusion period in October 2014 (last patient last visit, LPLV). Microbiological analyzes and data processing is expected to be completed one year after the LPLV. The study population is all women delivering a child by CS during the project period, at Department of Gynaecology and Obstetrics of OUH, HH and HSWJ.