1. Department of Obstetrics and Gynecology, Cantonal Hospital, Frauenfeld, Switzerland.
2. Division of Gynecology, Department of Obstetrics and Gynecology, University Hospital, Berne, Switzerland.
3. Division of Gynecology, Department of Obstetrics and Gynecology, University Hospital, Zurich, Switzerland.
4. Department of Obstetrics and Gynecology, Cantonal Hospital Bruderholz, Basel, Switzerland.