Antiphospholipid antibodies (antiprothrombinase and anticardiolipin) carry with them for mothers the risks of repeated fetal loss and of disorders of the blood clotting mechanism both before and after delivery. All the same screening does not have to be carried out routinely but should be reserved for patients who have already lost one fetus (intrauterine death after 12 weeks of amenorrhoea) and/or venous or arterial thrombosis. The diagnosis depends on a strict methodology and strict criteria for making a positive diagnosis. The treatment of these antibodies (with corticosteroids and intravenous immunoglobulin) or the prevention of possible thrombotic complications (using platelet antiaggregation/heparin) has to be decided taking into account the level of antibodies, previous obstetric and thrombotic history and the lupus symptomatology as shown by the patients. The overall success rate of treatment is between 53 and 81%.