Treatment of antiphospholipid syndrome in pregnancy.

Women with antiphospholipid antibodies (aPL = IgG anticardiolipin and/or lupus anticoagulants) and a history of either prior thrombotic events or pregnancy loss are at high risk during pregnancy for either another fetal death or thrombosis. The treatment of choice is anticoagulation with heparin. Both standard unfractionated heparin and low-molecular-weight heparin are used for prophylactic anticoagulation during pregnancy. The half-lives of either standard heparin, or low-molecular-weight heparin, and the peak values for each after subcutaneous injection, are lower than those in nonpregnant patients. Doses and injection intervals need to be adjusted when treating a pregnant woman. Clotting tests such as the activated partial thromboplastin time (aPTT) vary greatly during pregnancy, and the aPTT is often not even prolonged when antithrombotic levels of heparin are achieved. The aPTT is not a useful test when the patient has a lupus anticoagulant. Levels of plasma heparin are therefore needed to best care for pregnant women who need anticoagulation even for prophylaxis. Low-dose aspirin is often added empirically to heparin for treatment of aPL during pregnancy, but its efficacy has not been evaluated. Intravenous infusions of gamma globulins (IVGG) have been used as additional therapy when prior treatment with heparin during pregnancy failed to save the fetus, when severe and early onset preeclampsia has complicated a prior pregnancy (in such cases efficacy is unproven), or when there is an additional medical complication (such as immune thrombocytopenia) for which IVGG is an appropriate treatment. There are some situations in which treatment with corticosteroids is the best, or the only choice. However, corticosteroids should not be combined with heparin for long-term treatment during pregnancy because the risk for vertebral fracture is so high.