This study aimed to evaluate the predictive value of delta neutrophil index (DNI), a peripheral blood parameter, on perinatal outcomes in pregnant women with systemic lupus erythematosus (SLE). One hundred eighty-one participants, 78 pregnant women with SLE, and 103 healthy pregnant women were included in this retrospective study. Peripheral blood parameters including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and DNI taken in the first trimester were compared between groups. NLR, PLR, and DNI were significantly higher in the SLE group (p = 0.027, p = 0.007, p = 0.0001, respectively). The same parameters were not found to be significant in determining disease activity in pregnant women with SLE (p>0.05). When the predictive value of DNI for SGA in pregnancies with SLE was evaluated by receiver operating characteristic curve (ROC), the area under the ROC curve (AUC) was 0.666 (95% CI; 0.544-0.788, p=0.018) with 84.6% sensitivity, 53.8% specificity, 56.0% PPV, and 78.1% NPV at a cut-off value of 0.16. The predictive value of DNI according to ROC for stillbirth in pregnancies with SLE was AUC 0.731 (95% CI: 0.539-0.923, p = 0.019) with a cut-off value of 0.17, sensitivity of 90%, specificity of 51.5%, PPV of 58.5%, and NPV of 87.2%. Although DNI's prediction of SGA and stillbirth in pregnant women with SLE is encouraging, it needs more evidence from prospective studies with larger series.