Antiphospholipid antibodies and preeclampsia: A case-control study

Objective: To assess the association between the occurrence first of preecl ampsia and antiphospholipid antibodies. Methods: We conducted a prospective case-control study of 180 pregnant wome n with their first incidents of preeclampsia and no histories of thrombosis or systemic autoimmune diseases. Preeclampsia (n = 180) was defined as blo od pressure (BP) at least 140/90 mmHg after 20 weeks' gestation and protein uria at least 0.3 g per 24 hours. Two control subjects were matched to each case (n = 360). They were pregnant women without hypertension or proteinur ia and without histories of thrombosis or systemic autoimmune disease. Lupu s anticoagulant (activated partial thromboplastin time, diluted thromboplas tin time, platelet neutralization procedure) and anticardiolipin antibodies (immunoenzymatic assays) were assessed in both groups, and the coagulation state (levels of thrombin-antithrombin III complexes, fragments 1 + 2 of p rothrombin) was also evaluated. The analysis design was a sequential plan w ith 5% type I error and 95% power. Results: There was no association between antiphospholipid antibodies and p reeclampsia. The odds ratio for the association was 0.95 (95% confidence in terval 0.45, 2.61). Antiphospholipid antibodies were detected in eight of 1 80 preeclamptic women and in 19 of 360 controls. In contrast, there was a c lear, confirmed activation of coagulation during preeclampsia. Conclusion: Despite evidence of a prothrombotic state during preeclampsia, it is unlikely that antiphospholipid antibodies (lupus anticoagulant and an ticardiolipin anti-bodies) represent risk factors for preeclampsia among wo men with no previous preeclampsia and no histories of thrombosis or systemi c autoimmune disease. (Obstet Gynecol 2001;97:29-34. (C) 2001 by The Americ an College of Obstetricians and Gynecologists.)