1. Department of Women’s Health , University Clinical Centre Tuebingen , Tuebingen , Germany
2. Department of Gynecological Endocrinology, Beijing Obstetrics and Gynecology Hospital , Capital Medical University , Beijing , China , Phone: +49 7071 298 4801
3. Department of Obstetrics and Gynecology, Academic Hospital Weyertal , University Cologne , Cologne , Germany