Objective The objective of this paper is to compare adverse pregnancy outcomes between normal pregnancies and pregnancies with systemic lupus erythematosus (SLE), particularly focusing on uncomplicated SLE with remission. Methods A retrospective cohort study was conducted by accessing the Maternal-Fetal Medicine (MFM) Unit database and the full medical records of the women. The records of singleton pregnancies with SLE and no underlying disease were assigned as the study group and their medical records were reviewed. The low-risk pregnancies were randomly selected as the controls. The adverse pregnancy outcomes were compared between the control group vs women with SLE, control group vs uncomplicated SLE, and between the subgroups within the study group. Results Of 28,003 births during the study period, 1400 controls and 140 pregnancies with SLE were compared. The rates of fetal loss, preterm birth, small-for-date, low birth weight and preeclampsia were significantly higher in the study groups with a relative risk of 5.6 (95% CI: 2.9-10.9), 3.2 (95% CI: 2.5-4.1), 3.5 (95% CI: 2.4-4.9), 4.2 (95% CI: 3.4-5.3) and 2.9 (95% CI: 1.9-4.4), respectively. The increased rates of most adverse outcomes were still noted even in the cases of uncomplicated SLE. Among women with SLE, lupus nephritis, chronic hypertension, antiphospholipid syndrome, active disease at the onset of pregnancies, and proteinuria were significantly associated with such outcomes. Conclusions Pregnancies with SLE, even in uncomplicated cases with remission, increase the risk of poor pregnancy outcomes. The presence of lupus nephritis, chronic hypertension, antiphospholipid syndrome, active disease at the onset of pregnancies, and proteinuria were significantly associated with such outcomes.