A review of the literature and our own experience have shown that the three types of antibodies to phospholipids (APL) usually looked for (i.e. dissociated treponema serology, antiprothrombinase and anticardiolipin) increase the risk of foetal loss, irrespective of whether the mothers have or do not have systemic lupus erythematosus. The prevalence of APL may exceed 40 percent in some series of women who suffered at least 3 foetal losses. Conversely, the incidence of foetal loss (often late in pregnancy) in women with APL has been estimated at 25 to 75 percent, depending on the studies. The presence of lupus seems to increase the risk. There is no consensus on the best factor predictive of foetal loss (antiprothrombinase or one of the anticardiolipin isotypes). Foetal loss seems to be caused by thrombosis of the placenta, the origin of which remains controverted. The therapeutic escalade consists of abstention (in the first pregnancy), aspirin (about 100 mg/day), aspirin-corticosteroid combination or subcutaneous heparin, high-dose intravenous immunoglobulins and plasmapheresis. With these various methods, the birth of a normal child can be expected in almost every case.