1. Department of Obstetrics and Gynecology; Herlev Gentofte University Hospital; Copenhagen Denmark
2. Interdisciplinary Research Unit; Elective Surgery Center; Silkeborg Hospital; Silkeborg Denmark
3. Institute for Social Medicine and Epidemiology; University of Lübeck; Lübeck Germany
4. Department of Obstetrics and Gynecology; Odense University Hospital; Odense Denmark