Longitudinal Immature Platelet Fraction (IPF) Profiles and the Prediction of Spontaneous Abortion in Pregnancies Presenting With Threatened Miscarriage: A Prospective Cohort Study: Serial IPF and Threatened Miscarriage

Background: Threatened miscarriage is one of the most common complications of early pregnancy and remains a major clinical challenge because currently available clinical, ultrasonographic, and laboratory markers have limited ability to predict subsequent pregnancy loss. The immature platelet fraction (IPF), a readily available indicator of thrombopoietic activity, has recently emerged as a potential dynamic biomarker in several inflammatory and vascular disorders. However, its longitudinal behavior during early pregnancy has not been adequately investigated. Objective: To evaluate whether serial changes in IPF during the first week after presentation are associated with spontaneous abortion in women presenting with threatened miscarriage. Methods: This prospective cohort study included 150 women with singleton viable intrauterine pregnancies between 6 and 12 weeks of gestation who presented with vaginal bleeding and a closed cervix. Venous blood samples were obtained at presentation (T0), 48 h (T1), and one week (T2). Participants were followed until 20 weeks of gestation, and pregnancy outcomes were recorded as continuation or spontaneous abortion. Longitudinal changes in IPF were evaluated using repeated-measures statistical methods. Receiver operating characteristic (ROC) analysis was performed to assess the predictive performance of serial IPF measurements. Results: Thirty women (20%) experienced spontaneous abortion before 20 weeks of gestation. Baseline IPF values were comparable between the spontaneous abortion and pregnancy continuation groups (median 2.40% vs. 2.35%; p = 0.785). In contrast, serial measurements demonstrated significantly different temporal patterns between the groups (time-by-group interaction, p < 0.001). A decline in IPF of at least 20% during the first week after presentation predicted spontaneous abortion with an area under the ROC curve of 0.91, sensitivity of 88%, and specificity of 92%. Conclusions: Longitudinal assessment of IPF provides substantially greater prognostic information than a single baseline measurement in women presenting with threatened miscarriage. Serial IPF monitoring may represent a simple, inexpensive, and promising adjunctive biomarker for early risk stratification. External validation in larger multicenter cohorts is warranted before routine clinical implementation.