Embodiments herein relate to the field of screening tools for fetal/maternal wellness, and, more specifically, to biomarkers for gestational diabetes. In various embodiments, the methods may provide non-invasive and minimally-invasive screening tools for gestational diabetes that involve detection of changes in a proteomic profile of a test sample relative to a reference sample. In particular embodiments, the method may include determining whether a proteomic profile of a test sample from the subject includes at least one expression signature characteristic of gestational diabetes, wherein the proteomic profile comprises information on the expression of glycosylated fibronectin and glycosylated PSG, for example information on levels of fibronectin-SNA or a fibronectin-antibody complex, and PSG-AAL or a PSG-antibody complex. In some embodiments, the proteomic profile may also include information on the expression of adiponectin, sex hormone binding globulin (SHBG), C-reactive protein (CRP), a ratio of human chorionic gonadotropin (hCG) to placental lactogen, or a combination thereof.