The detection of anti-β2-glycoprotein I antibodies is associated with increased risk of pregnancy loss in women with threatened abortion in the first trimester

OBJECTIVE: This study was designed to evaluate whether the detection of serum antiphospholipid autoantibodies may be useful in predicting pregnancy outcome in women with threatened abortion in the first trimester. STUDY DESIGN: A group of 77 pregnant women of between 8 and 12 weeks' gestation with vaginal bleeding was tested for serum antiphospholipid, lupus anticoagulants, anticardiolipin, antinuclear antibodies, and anti-beta2-glycoprotein I antibodies, and was followed up until the spontaneous end of pregnancy. A control group composed of 15 healthy women with uncomplicated gestation was tested contemporarily for the same antibody panel. RESULTS: Of the 77 patients with threatened abortion, 32 (41.5%) progressed to deliver at term and 45 (58.5%) experienced early pregnancy loss. Among the antibodies evaluated, only anti-beta2-glycoprotein I was significantly more frequent in those women whose pregnancy resulted in spontaneous abortion (22/45, 49%) than in those who progressed to term (6/32, 19%) or in the control group (2/15, 13%; p=0.004). This difference was specific to the IgM isotype (p=0.001). After adjustment by multivariate analysis, the odds ratio for pregnancy loss associated with a positive beta2-glycoprotein I antibody test was 5.18 (p=0.001). CONCLUSION: The detection of anti-beta2-glycoprotein I antibodies is associated with an increased risk of pregnancy loss in women with threatened abortion in the first trimester.