ObjectiveTo determine the impact of lupus flares on maternal and fetal outcomes in pregnant patients with systemic lupus erythematosus(SLE).MethodsData was obtained from 46 pregnancies of 44 pregnant women with SLE.The relationship between lupus flares and pregnant outcomes,and the risk factors for adverse maternal and fetal prognosis were analyzed.T-test,X2 test or Fisher's exact test and Logistic regression were used for statistical analysis.Results① Lupus flares occurred in19(41％)pregnancies(group A) and stable lupus disease was observed in 27(59％) pregnancies(group B) during pregnancy.Compared to pregnancies in patients with stable lupus disease at the conception(n=32),pregnancies in patients with unstable lupus disease at the conception(n=8) had higher lupus flare during pregnancy( 100％ vs 16％,P＜0.05).(②) The common manifestations of lupus flares during pregnancy were lupus nephritis (LN) (11 cases),skin rashes (10 cases),arthritis (7 cases),and the common complication was infection ( 11 cases).(③) The incidence of premature labor,fetal growth retardation (FGR) and fetal loss in group A was 42％,47％ and 26％ respectively,which was significantly higher than that of the group B (7％,15％ and 0 respectively)(P＜0.05).There was no difference in the incidence of preeclampsia,fetal distress and neonatal asphyxia between the two groups ( 16％ vs 7％,16％ vs 19％,5％ vs O,respectively,P＞0.05).The incidence of premature labor and FGR in patients with active LN was higher than that of patients without active LN (55％ vs 11％,64％ vs 17％,respectively,P＜0.05).(④)The binary Logistic regression analysis showed that renal impairment,hypocomplementemia,aPL and serum urea nitrogen level were independent risk factors for premature delivery,FGR,fetal loss and fetal distress.Conclusion(①) Lupus flares during pregnancy increase the incidence of premature labor,FGR and fetal loss.Active LN during pregnancy can increase the incidence of premature labor and FGR.② Renal impairment,hypocomplementemia,aPL and serum urea nitrogen level are associated with adverse fetal outcomes in pregnant patients with SLE.