1. Clinic of Gynecological Endocrinology and Reproductive Medicine; University of Basel; Spitalstrasse 21 CH-4031 Basel Switzerland
2. Department of Biomedicine; University of Basel; Hebelstrasse 20 CH-4031 Basel Switzerland
3. Department of Gynecology and Obstetrics; Second Hospital of Jilin University; Changchun City Jilin Province P.R. China
4. Department of Surgery; University of Zürich; Rämistrasse 100 CH-8091 Zürich Switzerland