1. Centre for Research & Development, Clara Angela Foundation Witten and Berlin, Witten, Germany;
2. Department of Obstetrics Charite, Humboldt University Berlin, Berlin, Germany;
3. Department of Obstetrics and Gynecology, Bürgerhospital, Frankfurt, Germany;
4. Dr. Senckenberg Foundation, Johann-Wolfgang-Goethe University, Frankfurt, Germany;
5. Department of Obstetrics and Gynaecology, Universitätsklinikum des Saarlandes, Homburg, Germany;
6. Department of Pre-and Perinatal Medicine, Askelepios Barmbek, Hamburg-Barmbek, Germany;
7. Department of Perinatal Medicine, University of Florence, Florence, Italy;
8. Department of Perinatal Medicine, Isala Klinieken Zwolle, Zwolle, Netherlands;
9. Department of Maternal-Fetal Medicine, l’Hôpital de la Pitié Salpêtrière, Paris, France