1. Division of Prenatal Medicine and Gynecologic Sonography, Department of Obstetrics and Gynecology; University of Cologne; Cologne Germany
2. Division of Fetal Surgery, Department of Obstetrics and Prenatal Medicine; University of Bonn; Bonn Germany
3. Division of Obstetrics and perinatal Medicine, Department of Obstetrics and Gynecology; University of Essen; Essen Germany