Clinical and Hematological Correlates of Reactive Thrombocytosis in Neonates: A Single-Center Retrospective Analysis of Maternal and Perinatal Determinants in the Neonatal Intensive Care Unit

BACKGROUND AND AIM: Reactive thrombocytosis is defined as an increase in megakaryocyte count and production secondary to inflammation, malignancy, or anemia. Although cases of reactive thrombocytosis are frequently encountered in newborns admitted to the neonatal intensive care unit (NICU), neonatal thrombocytosis has not yet been fully elucidated. This study aimed to evaluate the maternal and neonatal medical characteristics of neonates diagnosed with reactive thrombocytosis in the NICU. MATERIALS AND METHODS: This retrospective, cross-sectional study included neonates with thrombocytosis (platelet count >450 × 109/L) who were admitted to our institution's NICU between January 1, 2021, and December 31, 2022. Children with suspected primary thrombocytosis were excluded from the study. Maternal and neonatal medical data were retrospectively analyzed using patient files. The cases were divided into 3 groups: platelet counts >450 and