The study assessed the expression level of the HIF1A, EPAS1 and HIF3A genes depending on clinical parameters such as the health of the pregnant woman, the method of delivery, the occurrence of stillbirths in previous pregnancies, the occurrence of hypertension during pregnancy, Body Mass Index (BMI) values before and during pregnancy, the intake of iron preparations during pregnancy, taking heparin during pregnancy and the presence of E. coli in vaginal culture, because it is the most common cause of bloodstream infections during pregnancy [25]. This evidence concerns the gene EPAS1 and Stillbirth.