1. Department of Obstetrics and Gynaecology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
2. Department of Obstetrics and Gynaecology, Spitalzentrum Biel, Biel, Switzerland
3. Department of Obstetrics and Gynaecology, SRO AG, Spital Langenthal, Langenthal, Switzerland
4. Department of Obstetrics and Gynaecology, University Hospital, Center Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland