1. Department of Neonatology, Medical University of Bialystok, Bialystok, Poland,
2. Department of Gynecology and Obstetrics, District Hospital in Bialystok, Bialystok, Poland,
3. Department of Perinatology, Medical University of Bialystok, Bialystok, Poland,
4. Department of Hematological Diagnostics, Medical University of Bialystok, Bialystok, Poland, and
5. Department of Statistics and Medical Informatics, Medical University of Bialystok, Bialystok, Poland