Maternal and foetal outcomes in pregnant patients with active lupus nephritis

The objective of this study was to determine the impact of lupus nephritis disease activity on maternal and foetal outcomes in pregnant patients with systemic lupus erythematosus (SLE). Medical records of all pregnant patients with SLE treated at our institution between 1976 and 2007 were reviewed. All patients met American College of Rheumatology classification criteria for SLE. Demographic data, history of lupus nephritis, nephritis disease activity and maternal and foetal outcomes of pregnancy were abstracted. Active lupus nephritis was defined as the presence of proteinuria >0.5 g/day and/or active urinary sediment with or without an elevation in serum creatinine (Cr). Quiescent lupus nephritis was confirmed in the presence of proteinuria <0.5 mg/day and inactive urinary sediment. We identified 58 patients with 90 pregnancies. Compared with pregnancies in SLE patients without renal involvement (n = 47), pregnancies in patients with active lupus nephritis (n = 23) were associated with a higher incidence of maternal complications (57% vs 11%, P < 0.001), whereas those with quiescent lupus nephritis (n = 20) were not (35% vs 11%, P = 0.10). Women with active lupus nephritis were more likely to deliver preterm than women without lupus nephritis, median of 34 weeks vs 40 gestational weeks, respectively (P = 0.002) and were more likely to suffer foetal loss (35% vs 9%, P=0.031). Active, but not quiescent, lupus nephritis during pregnancy is associated with a higher incidence of maternal and foetal complications compared with pregnancies in SLE patients without renal involvement.