Background: This study was designed to determine the effects of calcium-vitamin D supplementation on insulin resistance, inflammatory factor and biomarkers of oxidative stress among healthy pregnant women and pregnancy outcomes.

  Methods: This randomized double-blind controlled clinical trial was performed among 42 p regnant women, aged 18-40 year old who were carrying singleton pregnancy at 25 weeks of gestation. Pregnant women were randomly assigned to receive either 500 mg calcium-200 IU vitamin D supplements (n=21) or placebo (n=21) for 9 weeks. Fasting blood samples were taken at baseline and after 9-wk intervention to measure insulin resistance, high sensitivity C-reactive protein ( hs-CRP) and biomarkers of oxidative stress including plasma total antioxidant capacity (TAC) and total glutathione (GSH) . Newborn's weight, length and head circumference were measured during the first 24 h after birth.

  Result: Consumption of calcium-vitamin D supplements compared with the placebo resulted in a significant reduction of serum hs-CRP levels (-1856.76 vs. 707.13 µg/mL, P=0.006), a significant elevation of plasma TAC (89.29 vs. -9.37 mmol/L, P=0.03), serum vitamin D (2.49 vs. -1.72 ng/mL, P<0.0001) and calcium levels (0.6 vs. -0.1 mg/dL, P<0.0001). The supplementation led to a significant decrease in DBP (-1.9 vs. 3.1 mmHg, P=0.02) compared to placebo.

  Conclusion: In conclusion, consumption of calcium-vitamin D supplements for 9 weeks among pregnant women had the beneficial effects on metabolic profiles .