Antiphospholipid antibodies in early repeated abortions: a case-controlled study.

The relation among lupus anticoagulant (LAC), anticardiolipin antibodies (ACA), and repeated abortions was evaluated in a case-controlled study of 49 women with two or more unexplained spontaneous abortions (cases) compared with 141 control subjects, who had had one or more normal pregnancies and no previous spontaneous abortion. The women were admitted to the same hospital where the cases had been identified for acute conditions other than immunologic neoplastic, gynecologic or cardiovascular. LAC was detected in 7 out of 49 cases (14%, 95% confidence limits 8% to 26%) but in none of the 141 controls. Similarly, ACA were detected in four cases (8%, 95% confidence limits 0.3% to 30%) but no controls. These differences in frequency were statistically significant. These findings confirm that LAC and ACA are associated with a history of repeated abortions in clinically asymptomatic patients for immunologic conditions.