Contribution of the addition of anti-β2-glycoprotein to the classification of antiphospholipid syndrome in predicting adverse pregnancy outcome

Objectives. Anti-β2 glycoprotein 1 (a-β2GP1) was added to the criteria for antiphospholipid syndrome (APS) in 2005. However, its clinical significance with respect to complications of pregnancy is not well established. The aim of this study was to evaluate the association of laboratory findings of a-β2GP1 with events of thromboembolism or obstetric complications (pregnancy loss, placental dysfunction, intrauterine growth restriction, preeclampsia, fetal death, and preterm delivery) in women with clinical and laboratory evidence of APS. Methods. A retrospective cohort design was used. Ninety-one patients (total 394 pregnancies) referred to a tertiary medical center for evaluation of clinical features consistent with APS were divided into three groups: group A (n = 34), two positive tests for anticardiolipin (ACL) or lupus anticoagulant (LAC), in accordance with original APS classification (1998); group B (n = 18), two positive tests for a-β2GP1, in accordance with the revised APS criteria; and group C (n = 39), only one positive test for ACL or LAC. Results. Of the 52 women with APS (group A or B), 36 had primary disease, and 16 had secondary disease. On comparison of the groups, group B was characterized by a significantly higher rate of complicated pregnancy (83.3%) than groups A (47.1%) and C (76.9%), P = 0.007, and a higher rate of fetal loss (72.2%) than groups A + C (28.8%, P = 0.001). Conclusions. The findings suggest that the revised APS criteria are preferable to the original classification for the prediction of complicated pregnancy.