Objective: Micronutrient deficiency during pregnancy is associated with several complications. This study was designed to determine the effects of received multivitamin-mineral vs. multivitamin supplements on maternal, newborns' biochemical indicators, and birth size. Methods: This double-blind randomized-controlled clinical trial was conducted among 48 Iranian pregnant women, primigravida, aged 18-35 years old in their second and third trimester from December 2011 to September 2012. Subjects were randomly assigned to receive either the multivitamin-mineral (n=24) or multivitamin supplements (n=24) for 20 weeks. Fasting blood samples were taken at baseline and after a 20-week intervention of pregnant women as well as umbilical cord blood of the babies immediately after delivery to measure serum calcium, vitamin D, iron, magnesium, zinc and biomarkers of oxidative stress including plasma total antioxidant capacity and total glutathione. Results: Multivitamin-mineral compared to multivitamin supplementation resulted in a significant increase in maternal serum calcium (0.5 vs. -0.1 mg/dL, p=0.04) and magnesium levels (0.1 vs. -0.2 mg/dL, p<0.001). Furthermore, mean plasma total glutathione levels (1791 ± 566 vs. 1434 ± 622 µmol/l, p=0.04) of the newborns whose mothers received multivitamin-mineral were higher than those whose mothers received multivitamin supplements. Conclusions: Overall, multivitamin-mineral compared to multivitamin supplementation for 20 weeks during pregnancy resulted in a significant increase in maternal serum calcium and magnesium levels as well as a significant elevation of newborn plasma total glutathione levels.