Course of antiphospholipid antibodies in patients with primary antiphospholipid syndrome before, during and after pregnancy treated with low dose aspirin. Relationship of antibody levels to outcome in 7 patients.

We studied 7 patients with primary antiphospholipid syndrome (APS), who had had, between them, 28 fetal losses in 30 pregnancies. The 2 successful pregnancies had occurred 14 years previously. The patients had been followed for a mean of 20.5 months with a mean of 6.4 determinations of antiphospholipid antibodies (aPL) before becoming pregnant again. Serial determinations of aPL continued to be done throughout pregnancy. Patients were treated with low dose aspirin only except for one who had prednisone added at the time of an impending abortion. Five patients had successful outcomes and 2 had stillbirths. In the patients who had pregnancy loss, as well as in those who had other obstetric incidents there were abrupt changes in IgG, but not in IgM, levels. Levels of IgG aPL in patients with successful outcomes tended either to decrease gradually or to remain stable throughout. We conclude that patients with primary APS who had repeatedly unsuccessful pregnancies may show changes in their IgG levels during pregnancy that could indicate impending morbidity. In some of them low dose aspirin may prevent pregnancy loss.