Systemic lupus erythematosus (SLE) is mainly a disease of fertile women and the coexistence of pregnancy is by no means a rare event. How SLE and its treatment affects pregnancy outcome is still a matter of debate. Assessment of the reciprocal clinical impact of SLE and pregnancy was investigated in a cohort study. We reviewed the clinical features, treatment, and outcomes of 43 pregnant SLE patients with 51 pregnancies followed from 1993 to 2007 at a tertiary university hospital. The age of patients was 28.7 +/- 5.4 years and SLE was diagnosed at age of 23.0 +/- 6.1 years. Previous manifestations of SLE included lupus nephritis (14 patients) and secondary antiphospholipid syndrome (11 patients). Thirty-five pregnant patients (69%) were in remission for more than 6 months at the onset of pregnancy. Patients were being treated with low doses of prednisone (29), hydroxychloroquine (20), azathioprine (five), acetylsalicylic acid (51), and low molecular weight heparin (13). Sixteen pregnancy-associated flares were documented, mainly during the second trimester (42%) and also in the following year after delivery (25%). Renal involvement was found in 11 cases (68%). Spontaneous abortion occurred in 6%, 16% had premature deliveries, and 74% were delivered at term. No cases of maternal mortality occurred. No cases of fetal malformation were recorded. There was one intrauterine fetal death and one neonatal death at 24 gestational weeks. Pregnant women with SLE are high risk patients, but we had a 90% success rate in our cohort. A control disease activity strategy to target clinical remission is essential.