1. Department of Obstetrics, University Hospital of Zurich, Frauenklinikstrasse 10, 8091 Zurich, Switzerland
2. Faculty of Medicine, University of Zurich, Rämistrasse 71, 8091 Zurich, Switzerland
3. Department of Obstetrics and Gynaecology, Cantonal Hospital Baden, 5404 Baden, Switzerland
4. Department of Surgery & Transplantation, Swiss Hepatopancreatobiliary Laboratory, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland