1. Department of Obstetrics and Gynaecology; University Hospital of Schleswig-Holstein; Campus Luebeck; Luebeck Germany
2. Department of Gynaecological Endocrinology and Fertility Disorders; Ruprecht-Karls-University Heidelberg; Heidelberg Germany
3. Department of Obstetrics and Gynecology; Justus-Liebig-University Giessen; Giessen Germany