1. Department of Obstetrics and Gynecology, Helios Klinikum Erfurt, Germany
2. Klinikum Erfurt GmbH, Klinik für Frauenheilkunde und Geburtshilfe, Gorkistraße 6, Erfurt 99084, Germany
3. Department of Dermatology, Klinikum Darmstadt, Germany
4. Department of Gynecology and Gynecological Oncology, Universitätsklinik Essen, Germany
5. Department of Urolog, Universitätsklinik Großhadern , München, Germany
6. Institute of Medical Statisitics, , Freie Universität Berlin, Germany
7. 3M Medica, Borken, Germany