Pregnancies complicated by antiphospholipid antibodies: effect of prednisone on the activated partial thromboplastin time and antiphospholipid antibody levels.

Lupus anticoagulant is an anti-phospholipid autoantibody which is associated with several adverse pregnancy outcomes including recurrent pregnancy loss, intrauterine fetal death, and intrauterine growth retardation. Treatment of the mother during pregnancy with prednisone and low-dose aspirin increases the rate of delivering a viable infant. Furthermore, successful outcome has been associated with "correction" of the prolonged partial thromboplastin time by prednisone. I studied the effect of prednisone therapy (40-120 mg per day) on the partial thromboplastin time and anti-phospholipid antibody levels in eight pregnant women with lupus anticoagulant and correlated the observed changes with the pregnancy outcome. In all cases, the partial thromboplastin time declined during the treatment. Restoration of the partial thromboplastin time to the normal range was shown in six patients, of whom three had living infants and three had pregnancy losses. The anti-phospholipid antibodies were detected by an enzyme-linked immunoabsorbant assay. In two of five patients who had living infants, the antibody levels returned to normal range at the end of treatment, but the remained abnormal in three others as well as in three patients with pregnancy losses. This study demonstrates that although treatment with prednisone increases the successful pregnancy outcome of patients with lupus anticoagulant, the effect of the regimen on the partial thromboplastin time doe not predict the pregnancy outcome. The effect of prednisone on anti-phospholipid antibody levels is unpredictable and it is difficult to predict the therapeutic efficacy be determining the antibody levels.