The Thrombopoietic Signature of Preeclampsia: Diagnostic and Monitoring Insights from the Immature Platelet Fraction

<b>Background:</b> Preeclampsia is a major obstetric disorder characterized by platelet activation and dysregulated thrombopoiesis. While conventional platelet indices reflect platelet morphology, the immature platelet fraction (IPF) provides insight into thrombopoietic activity. This study assessed IPF discrimination at presentation and its early post-treatment change in preeclampsia while controlling for potential confounding factors. <b>Methods:</b> In a prospective design, demographic and laboratory parameters-particularly platelet indices-were evaluated in women with preeclampsia and normotensive pregnant controls. Measurements were obtained at diagnosis and repeated 24-48 h after treatment, including initiation of medical treatment or delivery. Logistic regression and ROC analyses were performed, adjusting for age and gestational age. <b>Results:</b> Sixty-four women with preeclampsia and 25 normotensive controls were included; the preeclampsia group was older (31.3 ± 5 vs. 28.4 ± 4 years), and delivery occurred in 73.4%. At diagnosis, IPF, MPV, and PDW were higher, and platelet counts were lower compared with controls. After treatment, IPF decreased markedly (ΔIPF = 3.4; <i>p</i> < 0.001), accompanied by reductions in MPV and PDW, while platelet counts remained unchanged in the preeclampsia group. ΔIPF showed subtype-related differences, being higher in late-onset preeclampsia. Only IPF retained an independent association with preeclampsia (OR = 27.29; <i>p</i> = 0.006), whereas age, platelet count, MPV, PDW, BUN, and CRP were not significant. On ROC analysis, IPF demonstrated strong diagnostic performance (AUC = 0.992; cut-off ≥4%), with 98.4% sensitivity and 100% specificity. <b>Conclusions:</b> Easily measurable as part of a routine complete blood count, IPF may support diagnostic evaluation and clinical monitoring, consistent with its early post-treatment decline and subtype-related patterns.