Antiphospholipid syndrome is a pro-thrombotic, pro-inflammatory condition defined by at least one clinical criterion and one laboratory finding. Clinical criteria are met by history of thrombosis or obstetric morbidity, including recurrent early pregnancy loss, fetal death, or delivery prior to 34 weeks gestation due to pre-eclampsia or placental insufficiency. Laboratory criteria are evidence of lupus anticoagulant or high titers of anticardiolipin or anti-ß 2 -glycoprotein-I IgG or IgM. Treatment during pregnancy is primarily based on anticoagulant therapy, either at prophylactic or therapeutic doses depending on thrombosis history. This treatment certainly reduces thrombosis risk and may also improve obstetric outcome.