1. Department of Paediatrics and Adolescent Medicine; University of Erlangen-Nuremberg; Erlangen Germany
2. Institute of Social Paediatrics and Adolescent Medicine; University of Munich; Munich Germany
3. Regional Centre for Social Paediatrics; Klinikum Konstanz; Konstanz Germany
4. Department of Obstetrics and Gynaecology; University of Erlangen-Nuremberg; Erlangen Germany
5. Department of Obstetrics and Gynaecology; Diakonische Dienste Hannover; Hannover Germany
6. Department of Obstetrics and Gynaecology; University of Aachen; Aachen Germany
7. Medical Research Laboratory; Department of Clinical Medicine; Faculty of Health; Aarhus University; Aarhus Denmark
8. Department of Paediatrics and Adolescent Medicine; University of Cologne; Cologne Germany