Serum osteopontin as a diagnostic marker for missed abortion: evidence from a prospective study

Objective: Osteopontin (OPN) is a multifunctional molecule involved in embryo implantation and blastocyst adhesion. Given its role at the maternal–fetal interface, OPN has been proposed as a potential biomarker for early pregnancy outcomes. The aim of this study was to evaluate the association between serum OPN levels and missed abortion in women presenting with early pregnancy bleeding. Material and Methods: In this prospective study, primigravid women between 6 and 11 weeks of gestation with confirmed fetal cardiac activity were enrolled. Participants were classified into three groups according to clinical presentation: normal pregnancy, threatened abortion, and missed abortion. Blood samples were obtained at admission, and serum OPN levels were measured using an enzyme-linked immunosorbent assay. Inflammatory markers including white blood cell count, neutrophil-to-lymphocyte ratio, C-reactive protein levels, and body mass index were also recorded. Results: The study cohort numbered 198 women, aged 18-42 years, with 38, 80 and 80 women in the normal pregnancy, threatened and missed abortion groups, respectively. OPN levels showed a significant and progressive increase with the lowest levels observed in normal pregnancies, higher levels in threatened abortion, and the highest levels in missed abortion (p<0.001). Receiver operating characteristic curve analysis demonstrated strong discriminative capacity of OPN for pregnancy loss (area under the curve =0.846, p<0.001). A cut-off value of 1.15 ng/mL was associated with 100% sensitivity, whereas a cut-off value of 2.15 ng/mL was associated with 100% specificity. Conclusion: Elevated serum OPN levels are associated with early pregnancy loss and may serve as a potential biomarker in missed abortion. However, these findings should be interpreted with caution given the exploratory nature of the analysis.