Should anticardiolipin tests be performed in otherwise healthy pregnant women?

Positive anticardiolipin and lupus anticoagulant tests are not confined to patients with the antiphospholipid syndrome, and the usefulness of these tests in healthy pregnant women is uncertain. This study sought to determine the prevalence of anticardiolipin antibodies and correlation with pregnancy outcome in 1449 pregnant women. Results were compared with 40 patients with the antiphospholipid syndrome. Persistence of positive anticardiolipin antibody tests was also ascertained. Twenty-six of 1449 sera (1.79%) were immunoglobulin G anticardiolipin positive, and 63 (4.3%) were immunoglobulin M anticardiolipin positive. Twenty-three of 26 positive for immunoglobulin G anticardiolipin and 55 of 63 positive for immunoglobulin M anticardiolipin results were low. Anticardiolipin positivity did not correlate with complications or outcome. Immunoglobulin G isotype and level distinguished patients with antiphospholipid syndrome from otherwise healthy women with positive anticardiolipin tests. In healthy pregnant women positive anticardiolipin tests occur infrequently, at low levels, and are rarely associated with adverse pregnancy outcome. This test should be requested only when the antiphospholipid syndrome is suspected.