1 Division of Prenatal Medicine and Therapy, Department of Obstetrics and Perinatal Medicine, University Hospital Marburg, Philipps University Marburg, Marburg, Germany.
2 Department of Prenatal Medicine and Fetal Therapy, Justus Liebig University Giessen, Giessen, Germany.
3 Department of Obstetrics and Gynecology, Baylor College of Medicine and Texas Children's Fetal Center, Houston, TX, USA.