1. Fetal Cardiology Center Type C, Department for Diagnosis and Prevention of Congenital Malformations; Medical University of Lodz and Polish Mother's Memorial Hospital; Lodz; Poland
2. Fetal Cardiology Center Type C, Perinatology and Perinatal Cardiology Center Medical University in Warsaw; Warsaw; Poland
3. Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology; Jefferson Medical College of Thomas Jefferson University; Philadelphia; PA; USA