Since the 1960s, antiphospholipid antibodies have been known to be associated with repeated miscarriages and fetal losses. Other complications of pregnancy, such as preterm birth, with pre-eclampsia or severe placental insufficiency were also frequently reported and are included in the current classification criteria of the antiphospholipid syndrome. The titer, isotype or antigen specificity of the antibodies may be important in risk determination. The pathogenesis of pregnancy failures is not only linked to the thrombophilic effect of antiphospholipid antibodies but also to a direct effect of antibodies on trophoblast differentiation and invasion. The study of experimental animal models provided sound evidence of the pathogenic role of antiphospholipid antibodies both in lupus-prone and -naive mice. The classification of pregnant antiphospholipid syndrome patients as being at a 'high risk' has completely changed their prognosis due to obstetric monitoring and the application of effective therapy. In fact, despite the high rates of complications and preterm delivery, a successful outcome can now be achieved in a large majority of cases.