Association of APRI, FIB-4, and FIB-5 Scores with Threatened Miscarriage

Objectives: This study aimed to compare the aspartate aminotransferase-to-platelet ratio index (APRI), fibrosis-4 index (FIB-4), and fibrosis-5 index (FIB-5) between women with threatened miscarriage and healthy pregnant controls, and to evaluate their discriminative performance. Methods: This single-center retrospective case-control study included 100 women with threatened miscarriage and 100 gestational-age-matched healthy pregnant controls within the first 12 weeks of gestation. Demographic, obstetric, ultrasonographic, and laboratory data were retrieved from electronic records. APRI, FIB-4, and FIB-5 were calculated from routine laboratory parameters. Group comparisons, binary logistic regression, and ROC analyses were performed. Results: AST, ALT, ALP, APRI, and FIB-4 were higher, while hemoglobin, platelet count, albumin, and FIB-5 were lower in the threatened miscarriage group (all p < 0.001). APRI (OR = 6.937), FIB-4 (OR = 89.114), and FIB-5 (OR = 0.766) were independently associated with case status. FIB-4 showed the highest discriminative performance (AUC = 0.929), followed by APRI (AUC = 0.903) and FIB-5 (AUC = 0.761). Conclusions: APRI and particularly FIB-4 showed good apparent discrimination between women with threatened miscarriage and healthy controls in this retrospective dataset. However, these indices should be interpreted as exploratory laboratory-derived markers rather than disease-specific biomarkers until validated in prospective multicenter studies.