Background: Idiopathic inflammatory myopathy (IIM) in pregnancy is uncommon but may result in complications for both mother and the fetus. Aim:In this systematic review, we summarized the current literature investigating outcomes of pregnancy related to the dermatomyositis/polymyositis (DM/PM) process. Content:We searched PubMed, Embase, Cochrane Library, and Web of Science databases and included 61 studies reporting the disease course, pregnancy outcomes, and management of both pregnancy and DM/PM in the final analysis.The specific information of 221 pregnancies was extracted and these pregnancies were divided into three distinct forms: pregnancies after disease onset (n = 159), pregnancies with new disease onset (n = 37), and pregnancies followed by postpartum onset (n = 25). In most cases, DM/PM disease activity remained stable or improved throughout pregnancy (80.2%) and the postpartum period (83.9%). Active DM/PM during pregnancy significantly increased the risk of stillbirth or neonatal death (12% vs. 1%, P = .005) and preterm birth (34.7% vs. 11%, P < .001). The rates of other poor outcomes (total fetal loss, low birth weight, and intrauterine growth retardation) were also increased in pregnancies with active disease. Mainstay treatments for active DM/PM during pregnancy are glucocorticoids and intravenous immunoglobins. Implications:The present results underline the importance of good control of myopathy in optimizing the pregnancy outcomes of women with DM/PM.