Introduction:
This study aims to determine the prevalence, clinical features, and methods of treating polycythaemia (PC) and hyperviscosity (HVS) syndrome in newborns over a 10-year period (2012–2022). Furthermore, it aims to determine whether there have been changes in the incidence of PC in the region encompassed by the study.

Material and methods:
This retrospective study sample included all the newborns with a diagnosis upon admittance and discharge of PC and HVS syndrome.

Results:
Incidence of PC and HVS syndrome was 0.8% (153/18.407) of the total number of babies born and 2.8% (153/5.483) of the treated newborn. Polycythaemia was more common in newborn males, in newborn weighing more than 2500 grams, with normal vitality scores, born at full term, and with other pathological conditions. The most common pathological condition in the newborn with PC was jaundice, and the most common symptoms were plethoric and dry skin, rash, and hypotonia. Furthermore, mothers with and without pathological conditions, who gave birth naturally, were equally represented.

Conclusions:
This 10-year study concludes that the prevalence of PC was constant over the years. Furthermore, mothers with and without pathological conditions, who gave birth naturally, were equally represented. The newborns were more frequently male, full-term babies, with good vitality scores and birth weights. Also, all the above leads to the conclusion that the newborns had passive PC that was not caused by a medical indication at birth, which led to the spectrum of various symptoms and pathological conditions that accompany PC. On the basis of the above results, it can be concluded that PC is most often passive in our region, which is why PC must be taken into consideration in the daily care of newborns despite the controversial opinions on the above-mentioned pathology.