Diagnostic Value of Paraoxonase-1 (PON-1), Adenosine Deaminase (ADA) and some Subclinical Inflammatory Markers in Recurrent Pregnancy Loss

Abstract Objective: This study evaluated the role of novel biomarkers in recurrent pregnancy loss (RPL) by assessing serum paraoxonase-1 (PON-1), adenosine deaminase (ADA), and subclinical inflammatory markers including neutrophil-to-lymphocyte ratio (NLR), white blood cell count (WBC), platelet count (PLT), plateletcrit (PCT), and red cell distribution width (RDW). Materials and Methods: A case-control study was conducted with 45 women with unexplained RPL (sampled during early pregnancy) and 45 healthy pregnant controls. Women with known causes of RPL such as antiphospholipid syndrome, thrombophilia, uterine anomalies, and endocrine disorders were excluded. None of the participants were receiving anticoagulant or anti-inflammatory therapy at the time of sampling. Serum PON-1 and ADA levels were measured, and inflammatory parameters were obtained from complete blood counts. Statistical analyses included independent t-tests, receiver operating characteristic (ROC) analysis, and logistic regression adjusted for potential confounders. Results: The RPL group had significantly higher WBC, PLT, PCT, NLR, and ADA levels, while PON-1 activity was significantly lower ( p < 0.05). PON-1 correlated inversely with ADA and NLR ( r = − 0.42 and r = − 0.39, p < 0.01). ROC analysis showed excellent diagnostic performance for PON-1 (AUC = 0.977) and ADA (AUC = 0.919). Logistic regression demonstrated that higher PON-1 levels were associated with lower odds of RPL (OR = 0.186, 95% CI: 0.10–0.32), whereas higher ADA levels were associated with increased odds (OR = 2.98, 95% CI: 1.56–5.69) ( p < 0.001 for both). Conclusion: PON-1 and ADA may serve as useful biomarkers for RPL. Their differential expression suggests a role in early risk identification and provides insight into inflammatory and oxidative mechanisms underlying RPL. Further multicenter studies with larger cohorts are warranted to validate these findings.