Jamilian M, et al. - This randomized, double-blind, placebo-controlled clinical trial determined the impacts of combined vitamin D and probiotic supplementation on metabolic status and pregnancy outcomes in 87 women with gestational diabetes (GDM). Compared with the placebo, vitamin D and probiotic co-supplementation significantly decreased fasting plasma glucose, serum insulin levels and homeostasis model of assessment-insulin resistance, and significantly increased the quantitative insulin sensitivity check index. Compared to the probiotic group alone, vitamin D and probiotic co-supplementation significantly lowered triglycerides, VLDL-cholesterol and hs-CRP, and significantly increased total antioxidant capacity (TAC) and total glutathione levels. In women with GDM, vitamin D and probiotic co-supplementation had beneficial effects on metabolic status.