A case-control study on the association of idiopathic recurrent pregnancy loss with autoantibodies against β2-glycoprotein I and annexin V

Whereas antiphospholipid antibodies (aPL) are associated with thrombotic events and recurrent spontaneous abortion (RSA), the contribution of anti-β2 glycoprotein 1 (β2GP1) and anti-annexin V antibodies as risk factors for RSA remain poorly understood. We investigated anti-β2-GPI and anti-annexin V IgM and IgG antibodies as potential risk factors for RSA in 200 women with more than three consecutive idiopathic RSA, and 200 age-matched, healthy, parous women. Pearson’s chi squared test analysis showed that while anti-β2-GPI IgG ( P = 0.416) and IgM ( P = 0.72) were comparable between patients and controls, elevated anti-annexin V IgG ( P = 0.006), but not IgM ( P = 0.084), was more pronounced in patients. Higher frequencies of elevated IgG-only ( P = 0.005), but not IgM-only ( P = 1.000; OR = 6.66), anti-annexin V antibodies were noted among patients. Multinomial regression analysis showed that body-mass index (overweight and obesity; P = 0.008), education status ( P < 0.001) and anti-β2-GPI IgM ( P = 0.033), but not IgG ( P = 0.723), were associated with early abortion, while anti-β2-GPI IgG ( P = 0.030) and anti-annexin V IgG ( P = 0.004) were associated with late RSA. For combined early-late RSA, the only variable selected was education status ( P < 0.001), and neither anti-annexin V nor anti-β2-GPI IgM and IgG was associated with early-late RSA. Accordingly, anti-annexin V and anti-β2-GPI should be regarded as independent risk markers of RSA.