1. Department of Obstetrics and Gynecology, University Medical Center Regensburg, Caritas-Hospital St. Josef, 93053 Regensburg, Germany
2. Second Department of Gynecology, Medical University of Lublin, 20-954 Lublin, Poland
3. Department of Gynecology and Obstetrics, University Medical Center Göttingen, 37075 Göttingen, Germany