Is there a role for antithrombotic therapy in the prevention of pregnancy loss?

The antiphospholipid syndrome (APS) is now emerging as an important cause of recurrent pregnancy loss. A variety of treatments, including steroids, aspirin, heparin and immunoglobulin, alone or in combination, have been assessed in experimental studies and in clinical trials. Steroids are no longer recommended as first-line therapy for patients with APS without overt lupus, because they are associated with significant foetal and maternal morbidity. Based on data from recent trials, heparin plus low-dose aspirin appears to be the regimen of choice for patients with APS who have a history of thrombosis or pregnancy losses with aspirin alone. Aspirin is safe in pregnancy. Subcutaneous heparin does not cross the placenta and therefore has no adverse effects on the foetus. For the mother, however, potential side effects of heparin treatment include bleeding, thrombocytopenia and osteoporosis. Warfarin must be avoided during the first trimester but may have a role to play subsequently in certain subsets of patients. Some studies have demonstrated that combined therapy with prednisone and aspirin, or with heparin and aspirin, may improve the outcome in women with autoimmune disorders who are undergoing in-vitro fertilization.