The association of AT-III and D-Dimer with unexplained recurrent spontaneous abortion and their diagnostic value for prethrombotic state.

Objective: This study aimed to investigate the role of antithrombin III (AT-III) and D-dimer (D-Dimer) in patients with unexplained recurrent spontaneous abortion (URSA); Methods: Sixty pregnant women with URSA (AEP group), 80 non-pregnant women with a history of URSA (ANP group), 50 healthy women in early pregnancy (NEP group) and 50 healthy non-pregnant women (NNP group) were retrospectively enrolled. Their serum AT-III and D-Dimer levels were measured. The patients in the ANP group were divided into three subgroups according to the number of miscarriages: 3 miscarriages (32 cases), 4 miscarriages (22 cases), and >4 miscarriages (26 cases), and the differences in serum AT-III and D-Dimer levels among these subgroups were compared. The patients in the AEP group were monitored for changes in AT-III and D-Dimer levels, and finally the diagnostic value of AT-III and D-Dimer levels were calculated for the prethrombotic state of URSA.

Results: (1) AT-III and D-Dimer levels differed significantly among the 4 groups (P<0.05); (2) As the number of miscarriages increased, D-Dimer levels elevated and AT-III levels decreased, with significant differences among three subgroups (P<0.05); (3) As the treatment proceeded, patients in AEP and ANP groups showed a tendency for a gradual increase in AT-III levels and a significant decrease in D-Dimer levels, with significant differences before and after treatment (P<0.05); (4) The diagnostic AUC of AT-III and D-Dimer in the prediction of prethrombotic state of URSA were 0.8922 (95% CI=0.8026-0.9819, P<0.0001) and 0.8776 (95% CI=0.7643-0.9909, P<0.0001).

Conclusion: AT-III and D Dimer levels are closely associated with URSA. The results of this study have preliminarily confirmed the feasibility of applying AT-III and D Dimer to screen the prethrombotic state of URSA, and their clinical application will help provide a reference for determining the cause of miscarriage in the infertile population with URSA and facilitate successful pregnancy.