1. Department of Paediatrics and Adolescent Medicine; University of Erlangen-Nuremberg; Erlangen; Germany
2. Department of Obstetrics & Gynaecology; University of Erlangen-Nuremberg; Erlangen; Germany
3. Department of Obstetrics & Gynaecology; University of Freiburg; Freiburg; Germany
4. Department of Obstetrics & Gynaecology; Städtisches Klinikum München; Munich; Germany
5. Department of Obstetrics & Gynaecology; Ludmillenstift Meppen; Meppen; Germany
6. Department of Obstetrics & Gynaecology; Diakonische Dienste Hannover; Hannover; Germany
7. Department of Paediatrics and Adolescent Medicine; University of Cologne; Cologne; Germany