1. Neonatal Department, Collegium Medicum of Cardinal Stefan Wyszynski University, 01-938 Warsaw, Poland
2. Department of Neonatology and Intensive Care, Medical University of Warsaw, Karowa 2, 00-315 Warsaw, Poland
3. Clinical Department of Neonatology, Central Clinic Hospital of Ministry of Interior and Administration, 02-591 Warsaw, Poland
4. Neonatal and Intensive Care Department, Institute of Mother and Child, 01-211 Warsaw, Poland