A study of the association between the early pregnancy thrombosis-thyroid axis and pregnancy outcomes in patients with recurrent spontaneous abortion.

Background: Recurrent spontaneous abortion (RSA) is a severe, yet common, pregnancy complication. Thrombophilia and thyroid dysfunction are critical factors altering placental microcirculation and embryonic development, although the synergistic predictive value of these two conditions for RSA pregnancy outcomes remains undetermined. Objective: To investigate the factors influencing pregnancy outcomes in patients with RSA; analyze the association between early pregnancy markers (including coagulation and fibrinolysis, platelet function, and thyroid function) and pregnancy outcomes in patients with RSA; identify independent risk factors and evaluate their predictive performance; explore the association between thrombotic markers and thyroid function parameters in the RSA population; elucidate the regulatory mechanisms of the thrombosis-thyroid function axis; and provide evidence-based support for early clinical risk prediction. Methods: We included 400 patients with RSA who were enrolled between January 2022 and December 2024 after screening and categorized them into successful pregnancy and pregnancy loss groups. Baseline clinical data and 20 early pregnancy laboratory parameters were collected. Univariate and multivariate logistic regression analyses were performed to screen risk factors. Spearman correlation analysis was used to assess thrombotic-thyroid axis correlations, and receiver operating characteristic (ROC) curves were adopted to evaluate the predictive value of relevant indicators. Results: In intergroup comparison, the pregnancy loss group exhibited significantly higher antithrombin III (AT), protein C (PC), protein S (PS), thrombin time (TT), adenosine diphosphate (ADP), arachidonic acid (AA), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) levels (P < 0.05), whereas the successful pregnancy group had higher D-dimer (DD), fibrinogen (FIB), and prothrombin activity (PA) levels (P < 0.05). Significant intergroup differences were not observed in activated partial thromboplastin time (APTT), prothrombin time (PT), free triiodothyronine (FT3), homocysteine (HCY), and antinuclear antibodies (ANA). Multivariate logistic regression demonstrated that elevated PS, increased ADP/AA-induced platelet aggregation rate, elevated FT4 and TSH, and reduced DD were independent risk factors for recurrent pregnancy loss (P < 0.05). Thrombotic markers and thyroid function markers showed widespread moderate-to-strong positive correlations in the successful pregnancy and pregnancy failure groups; however, cross-system synergistic correlations were significantly weaker in the pregnancy failure group, with correlation coefficients between AT and TSH of 0.19 and -0.0573, respectively, and a P-value of 0.013 for the between-group comparison (P < 0.05). The ROC analysis exhibited that the area under the curve of the single DD indicator for predicting pregnancy loss was 0.591 (95% confidence interval: 0.536-0.647), showing low-to-moderate predictive efficacy. Conclusion: There is a certain correlation between coagulation and thyroid function, with differences existing among patients with recurrent miscarriage but different pregnancy outcomes. Combined testing of PS, DD, ADP, AA, FT4, and TSH during early pregnancy may provide supplementary information for risk assessment in individuals with RSA.