1. Department of Gynecology and Obstetrics, University Medical Center Mainz, Langenbeckstraße 1, 55131 Mainz, Germany
2. Department for Gynecology, Obstetrics and Reproductive Medicine, Saarland University Hospital, 66421 Homburg, Germany
3. Department of Gynecology and Obstetrics, University Medical Center Augsburg, Stenglinstr. 2, 86156 Augsburg, Germany