1. Frankfurt Centre for Bone Health, Frankfurt, Germany
2. Philipps-University of Marburg, Marburg, Germany
3. Dpt. of Obstetrics and Gynaecology, Centre for Ultrasound and Prenatal Medicine, Buergerhospital and Clementine Childrenʼs Hospital Frankfurt a. M., Dr. Senckenberg Foundation and
Johann-Wolfgang-Goethe University of Frankfurt, Frankfurt, Germany
4. Dpt. Of Obstetrics and Prenatal Medicine, Asklepios Clinic Barmbek, University of Semmelweis, Hamburg, Germany