1. Department of Obstetrics and Gynecology, University Hospital, LMU Munich, 80337 Munich, Germany
2. Department of Obstetrics and Gynecology, Medical University of Graz, 8010 Graz, Austria
3. Institute of Pathology, Faculty of Medicine, LMU Munich, 80337 Munich, Germany
4. Department of Obstetrics and Gynecology, University Hospital Augsburg, 86156 Augsburg, Germany