1. Faculty of Medicine, University of Bern, Bern, Switzerland.
2. Department of Statistical Analysis, Medizin and Service GmbH Sachsen, Chemnitz, Germany.
3. Department of Obstetrics and Gynaecology, University Hospital Bern, Inselspital, Switzerland.
4. Division of Gynaecological Endocrinology and Reproductive Medicine, Department of Gynecology and Obstetrics, University Hospital Frankfurt, Frankfurt am Main, Germany.
5. Department for Gynaecological Endocrinology and Fertility Disorders, University Hospital Heidelberg, Heidelberg, Germany.