1. Department of Obstetrics and Prenatal Medicine, University of Bonn, 53127 Bonn, Germany
2. Department of Pediatric Cardiology, University Hospital RWTH Aachen, 52074 Aachen, Germany
3. Division of Prenatal Medicine, Gynecological Ultrasound and Fetal Surgery, Department of Obstetrics and Gynecology, University of Cologne, 50937 Cologne, Germany