Background The lupus flare rate during pregnancy was reduced with pre-pregnancy counseling and effective strategies. However, limitation of using immunosuppressant, the outcome of the lupus pregnancies with renal flare can be worse than the lupus patients without pregnancy.
Objectives The aims of this study were to compare clinical manifestations of pregnancy complications in lupus mothers with and without LN and to identify predictors for LN flares during pregnancy. In the case of renal flare during pregnancy, the long term prognosis has not been established. Therefore, we assessed the change in proteinuria and glomerular filtration rate (GFR) during a year after delivery.
Methods We performed a retrospective analysis of 183 pregnancies in 132 SLE patients managed in Catholic University Medical Center, Korea. Demographic data, SLE clinical manifestations and treatment, and obstetric outcomes were recorded from medical charts. Laboratory data included blood chemistry, urinalysis, spot urine protein to creatinine ratio or protein level from 24 hours urine collection, C3 and C4 level were collected from before pregnancy, during pregnancy, after 1 month, 6 months and 1 year after delivery.
Results 76 pregnancies had history of LN before conception. Pregnancies with history of LN had more adverse obstetric outcomes. Most of LN flare cases were reactivated and 4 cases (5.3%) became inactive during pregnancy. LN flare was predicted by high serum uric acid level (OR 1.843; 95% CI, 0.991-3.426; P=0.053). Twelve patients achieved a complete remission within 3 months after delivery but 15 patients showed persistent proteinuria or decreased GFR after 1 year from delivery. The peak level of proteinuria was not different between remission and persistent LN, but pregnancies who had attained a ≥50% reduction in urine protein at 6 months were significantly low in persistent after 1 year group. A ≥50% reduction in urine protein at 6 months predicts a favorable longterm outcome in renal flares during pregnancies (OR 0.132; 95% CI, 0.034-0.525; P=0.004).
Conclusions Lupus mothers with LN gave successful living births, but still there were more maternal and fetal comorbidity including LN flares. Baseline uric acid level was the only predictor for LN flare during pregnancy among the pregnancies with history of LN. The long-term renal outcome of LN during pregnancy was not inferior comparing with non-pregnant lupus patients. To reduce proteinuria to a level more than 50% within 6 months is important.
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Disclosure of Interest : None declared