Among 165 patients with systemic lupus erythematosus (SLE), we observed 21 pregnancies in 19 patients since 1987. The mean duration of disease at the time of pregnancy was 4.5 +/- 3 years. All but three patients required immunosuppressive treatment before and during pregnancy. The effect of pregnancy on the course of SLE was studied. Severe disease exacerbations were rare and largely confined to patients with renal involvement. Most patients showed elevated titers of dsDNA antibodies during pregnancy but clinical activity of disease was usually mild. Complement C3 decrease appeared to be the most sensitive marker for pregnancy-related complications. The detection of antibodies to phospholipids was frequent during pregnancy in contrast to a low prevalence before and after pregnancy. Their presence could be associated with intrauterine growth retardation. Preterm delivery before the 37th week of pregnancy had to be performed in the majority of patients. None of the patients experienced abortion although three patients had to delivered in the 29th week of pregnancy because of increasing symptoms of pre-eclampsia. Two of these children died and the third child suffered from intracranial hemorrhage in the early postpartum period. Our data demonstrate that successful pregnancy outcome was related to a gestational age of more than 32 weeks, making careful monitoring and appropriate therapeutic management necessary.