Objectives Our goal with this study was to determine the most important predictors for each of the main adverse pregnancy outcomes in SLE patients.

Methods Patients with systemic lupus erythematosus were retrospectively analyzed from 1990 to 2020. Maternal and fetal complications in pregnant women with SLE were retrieved. We compared clinical and analytical characteristics of SLE patients with adverse pregnancy outcomes to controls with SLE diagnosis without adverse pregnancy outcomes. Qualitative data were analyzed by Chi-square test and Fisher’s exact test. Continuous variables were analyzed by using Student’s t test. Multiple logistic regression was performed to determine the predictive factors for adverse pregnancy outcomes with adjustment of confounding factors.

Results 135 multiparous women were included (43% with adverse pregnancy outcomes). A total of 57 pregnancies (42%) were linked to adverse outcomes. The occurrence of abortion was correlated with anti-DNAds (β=0.71. p=0.04), renal involvement (β=0.28, p 0.03), antiphospholipid antibodies (β=0.29, p 0.03), ESR elevation (β =0.81, p=0.02) and CPR elevation (β =0.91, p=0.01). Stillbirth was also correlated with renal involvement (β= 0.26, p =0.04), antiphospholipid antibodies (β=0.22, p=0.03) and ESR elevation (β =0.53, p=0.02). Preeclampsia was correlated with direct Coombs positivity (β=0.42, p=0.01), serositis (β=0.31, p=0.02), ESR elevation (β =0.52, p=0.03) and CPR elevation (β =0.32, p=0.04). Neonatal Lupus was correlated with anti-RNP (β=0.16, p=0.03) and anti-Ro/SSA (β=0.16, p 0.02).

Conclusions The most unfavorable pregnancy outcome in women with SLE was spontaneous abortion. Renal involvement, anti-DNAds positivity, antiphospholipid antibody positivity, anti-Ro/SSA, elevated ESR and a younger age at disease onset increased the risk of pregnancy complications.