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 <700 × 109/L, 700 and <900 × 109/L, and 900 and <1000 × 109/L; gestational age was divided into 2 groups: <37 gestational weeks (GH) (preterm) and ≥37 to 42 GH (term); maternal age was divided into 3 groups: 20 years or younger, 20 to 34 years old, and 35 years or older; and birth weight was divided into 3 groups: <2500 g, 2500 to 3999 g, and ≥4000 g. The groups were then compared. Statistical significance was set at P <0.05.

CONCLUSION

A negative correlation was observed between mean platelet volume (MPV) and hemoglobin (Hb) levels at admission, as well as between MPV and platelet counts. The mean platelet count at the time of thrombocytosis was significantly higher in term cases than in preterm cases. Platelet counts were higher in the macrosomic group than in the nonmacrosomic group. Decreased Hb levels and increased C-reactive protein (CRP) levels were associated with severe thrombocytosis. Reactive thrombocytosis resolved spontaneously without complications and did not require any clinical intervention.