What blood tests are recommended for individuals experiencing recurrent miscarriage?

Blood Tests for Recurrent Miscarriage Evaluation

Blood tests for individuals experiencing recurrent miscarriage should include antiphospholipid antibodies (lupus anticoagulant and anticardiolipin antibodies), thyroid function tests with thyroid peroxidase antibodies, and thrombophilia testing in selected cases. 1

Core Blood Tests for All Patients with Recurrent Miscarriage

• Antiphospholipid antibodies, including lupus anticoagulant and anticardiolipin antibodies, should be tested in all women with recurrent miscarriage 1, 2
• Thyroid function tests and thyroid peroxidase (TPO) antibodies should be performed to identify thyroid dysfunction 1, 2
• Complete blood count to assess for underlying hematological conditions 3

Thrombophilia Testing in Selected Cases

• Testing for Factor V Leiden mutation is recommended for women with second-trimester losses 1, 2
• Prothrombin G20210A mutation testing should be considered for women with second-trimester losses 1, 2
• Protein S deficiency testing is indicated for women with second-trimester losses 1, 2
• Testing for sticky platelet syndrome may be valuable as it accounts for approximately 21% of procoagulant defects in recurrent miscarriage 3
• Tissue plasminogen activator (TPA) deficiency testing should be considered as it accounts for about 9% of procoagulant defects 3

Specialized Blood Tests Based on Clinical Context

• Expanded antiphospholipid antibody panel including antiphosphatidyl-serine, -inositol, -ethanolamine, -choline, -glycerol, and antiphosphatidic acid antibodies may be valuable, as 24% of patients with antiphospholipid syndrome have only these subgroup antibodies 3
• Thromboelastography (TEG) may be useful as women with recurrent miscarriages have been found to have an underlying prothrombotic state with significantly higher maximum amplitude (MA) and lower rate of clot lysis 4
• A prepregnancy MA ≥ 64 mm on TEG has a sensitivity of 68% and specificity of 82% to predict subsequent miscarriage 4

Tests That Are Not Routinely Recommended

• Routine testing for protein C, antithrombin deficiency, and methylenetetrahydrofolate reductase mutation is not recommended 1
• Immunological screening such as HLA typing, cytokine tests, and natural killer cell tests should not be routinely offered outside a research context 1
• Infection screening is not routinely recommended 1

Timing and Interpretation of Testing

• Antiphospholipid antibody testing should be performed prior to pregnancy 1
• TEG parameters should be assessed in the non-pregnant state, as they have been shown to correlate with pregnancy outcomes 4
• Thrombophilia testing results should guide management decisions regarding anticoagulation therapy 2, 5

Clinical Implications of Test Results

• Women diagnosed with antiphospholipid syndrome should be offered aspirin and heparin from a positive test until at least 34 weeks of gestation 1, 5
• Women with thyroid dysfunction may benefit from levothyroxine supplementation, though it's not routinely recommended for euthyroid women with TPO antibodies 1
• Women with procoagulant defects may benefit from preconception aspirin (81 mg/day) and postconception heparin (5000 U every 12 hours) to term, with reported success rates over 98% 3, 6

Practical Approach to Testing

• Initial evaluation should include antiphospholipid antibodies and thyroid function tests for all women with recurrent miscarriage 1, 7
• Consider thrombophilia testing for women with second-trimester losses or strong family history of thrombosis 2, 1
• TEG may provide valuable information about underlying prothrombotic states that conventional coagulation tests might miss 4
• Testing should be performed before conception when possible to guide management during subsequent pregnancies 5, 7