Anti-phosphatidylserine, anti-cardiolipin, anti-β2 glycoprotein I and anti-prothrombin antibodies in recurrent miscarriage at 8-12 gestational weeks

Objective: To investigate the association of antibodies to β2-glycoprotein I (anti-β2GPI), cardiolipin (ACA), phosphatidylserine (anti-PS) and prothrombin (anti-PT) with recurrent spontaneous miscarriage (RSM).

Study design: Case-control study involving 277 RSM cases and 288 controls: autoantibody levels were measured by ELISA. Differences between cases and controls were analyzed by nonparametric Mann-Whitney test, and logistic regression was used in analyzing the association of autoantibodies with RSM.

Results: Anti-PS IgG, ACA IgM and IgG, and anti-PT IgM were significantly associated with RSM risk, and differential antibody association was noted according to BMI and primary and secondary RSM. Higher prevalence of elevated anti-PS IgG was seen in cases, with the strongest risk above the 99th percentile. For ACA IgM, 28 cases (10.1%) and 5 controls (1.7%) were positive, with increasing OR for increasing cut-off points, which was significant at antibody titers >99th percentile. For ACA IgG, 101 cases (36.5%) and 13 controls (4.5%) were positive, with graded increase in OR for increasing cut-off points, which was significant at titers >90th percentile (maximal at titers >99th percentile). For anti-PT, 23 cases (12.0%) and 9 controls (6.1%) were positive, with increased OR at titers >90th percentile. Regression analyses confirmed the independent association of anti-PS IgG, ACA IgM and IgG with RSM, and significant RSM risk was associated with high anti-PS IgG (P<0.001) and ACA IgM (P<0.001) titers, and a dose-dependent increase in RSM risk was seen with progressively increased ACA IgG titers. No significant association existed between anti-PT IgM and RSM.

Conclusion: Elevated ACA IgM and IgG, and anti-PS IgG antibodies are positively associated with RSM.