1. University of Witten-Herdecke, Witten, Germany
2. Department of Obstetrics and Gynecology, Rheinlandklinikum Dormagen, Dormagen, Germany
3. Department of Obstetrics and Gynecology, University of Stellenbosch, Stellenbosch, South Africa
4. Pelvic School Saarbrücken, University of Homburg, Homburg, Germany
5. Department of Obstetrics and Gynecology, University Witten-Herdecke, Witten, Germany
6. Department of Anesthesiology, University of Cologne, Rheinlandklinikum Dormagen, Dormagen, Germany
7. Department of Obstetrics and Gynecology, University of Kiel, Kiel, Germany