Background: Systemic lupus erythematosus (SLE) is a multi-systemic inflammatory disease that mainly affects women of childbearing age. Development of SLE during pregnancy increases the risk of some maternal and fetal complications. We herein present a pregnant woman with new-onset SLE during pregnancy. Case description: A 30-year-old pregnant woman with a gestational age of 30 weeks and twin pregnancy was referred to a hospital because of bradycardia and arrhythmia of fetuses during routine pregnancy checkups. The patient was later diagnosed with SLE and received hydroxychloroquine and dexamethasone. During the course of treatment, the patient developed erythematosus skin lesions and was hospitalized for further evaluations. Various consultations were made. Given the overall conditions of the mother and fetuses, caesarean section was performed at week 34 of pregnancy. Finally, the patient was discharged with good general condition after one month of hospitalization. Conclusion: Active SLE during pregnancy is associated with an increased risk of maternal and fetal complications. It is essential to consider the impact of pregnancy on the disease, the impact of the disease on fetal health and the safety of medications used during pregnancy and lactation. For improved fetal and maternal outcomes, a multidisciplinary approach comprising of gynecology, neonatology and internal medicine should be taken when treating pregnant women with SLE.