Active but not quiescent lupus nephritis during pregnancy is associated with a higher rate of adverse obstetric outcomes: Analysis of a prospective cohort

Objective To compare the maternal‐fetal/neonatal outcome in patients with systemic lupus erythematosus (SLE) with and without lupus nephritis (LN) in remission or with active disease. Methods A prospective cohort of pregnant patients with SLE (ACR 1997 criteria) was studied from January 2009 to December 2021. Demographic, clinical, biochemical, and immunological variables as well as the usual maternal‐fetal/neonatal complications were recorded. We compared four groups according to the status of SLE during pregnancy: patients with quiescent SLE without lupus nephritis, patients with active SLE without lupus nephritis, patients with quiescent lupus nephritis, and patients with active lupus nephritis. Statistical analysis included descriptive statistics, bivariate analysis, and Cox regression analysis. Results A total of 439 pregnancies were studied, with a median age of 28 ± 6, SLE duration of 60 months (interquartile range 36–120). A higher frequency of maternal and fetal/neonatal complications was observed in patients with active SLE with or without lupus nephritis. Multivariate analysis showed that active LN was a risk factor for gestational hypertension (hazard ratios [HR] 1.95; 95% confidence intervals [CI]: 1.01–6.39), premature rupture of membranes (HR 3.56; 95% CI: 1.79–16.05) and more frequent cesarean section (HR 1.82; 95% CI: 1.13–2.94). Conclusion LN is associated with a higher frequency of maternal complications, especially in those patients with active disease during pregnancy, and those maternal complications had an impact on poor fetal/neonatal outcomes. Strict control and timely care of LN could improve the obstetric prognosis. Synopsis In this prospective cohort, active lupus nephritis during pregnancy was associated with an increased rate of maternal and fetal/neonatal complications.