RESUMEN
Systemic Lupus Erythematosus in an autoimmune disease of unknown etiology, which is seen more frequently in women than in men, especially in the reproductive age range, and which when associated with pregnancy may be lethal if the diagnosis is not made opportunely or treatment is inadequate. This report presents two cases of systemic lupus erythematosus during pregnancy one of which was diagnosed during the first trimester and which, with good prenatal care, respond well to treatment with prednisone and remained inactive during the pregnancy resulting in a favorable outcome. The second case was diagnosed in the second trimester with select manifestations of the disease activity which evolved poorly resulting in a fatal outcome for mother and fetus.