For a long time, systemic lupus erythematosus remains an insufficiently studied problem of rheumatology, the factors influencing the development and progression of the disease are not clear. The hormonal factor remains one of the possible triggers in the development of the disease in predisposed individuals. The course of pregnancy in patients with systemic lupus erythematosus is always associated with multiple risks. The onset of the disease during pregnancy often leads to the death of the fetus and the threat to the life of the mother. At the present stage, thanks to the possibilities of modern diagnostics and treatment, the prognosis for the life and health of both mother and fetus has improved. A case of the development of systemic lupus erythematosus during pregnancy and successful therapy with corticosteroids and belimumab is presented.