Antibodies against phospholipids are a risk factor for thrombotic disorders, but also for foetal death, pre-eclampsia, foetal distress and dysmaturity. This group of antibodies (aPLab) includes lupus anticoagulant (LAC) and anticardiolipin antibodies (aCL). These antibodies are encountered in patients with systemic lupus erythematosus (SLE), but also in patients with lupus-like disease and in women with (a history of) symptoms compatible with the antiphospholipid syndrome. Screening for a aPLab is advisable in these patients when they want to conceive and in women with recurrent foetal death after the 12th week of pregnancy. It is not clear if the antibodies exert a direct noxious action or are an accompanying phenomenon. Secondary prevention is possible with acetylsalicylic acid (80 mg/day), if desired in combination with subcutaneous heparin (5000-12,000 units twice daily). The thrombosis prophylaxis should be continued for 6 weeks after delivery.