Efficacy of two different doses of oral vitamin D supplementation on inflammatory biomarkers and maternal and neonatal outcomes

Hypovitaminosis D during pregnancy is suggested to have a link with complications in both mother and infant. We aimed to evaluate the efficacy of two doses of vitamin D3 supplementation during pregnancy on maternal and cord blood vitamin D status, inflammatory biomarkers, and maternal and neonatal outcomes. A total of 84 pregnant women (gestational age of <12 weeks) were randomly allocated to one of two groups: (a) 1,000-IU/d vitamin D and (b) 2,000 IU/d. Biochemical assessments (25-hydroxycalciferol (25(OH)D), hs-CRP, and cell-culture supernatant concentrations of IL-1 beta, IL-6, and TNF-alpha) of mothers were performed at the beginning and 34 weeks of gestation. Assessments of infants at delivery comprised cord blood serum concentrations of 25(OH)D, hs-CRP, IL-1 beta, IL-6, TNF-alpha, birth sizes, and Apgar score. Circulating concentrations of 25(OH)D increased in both intervention groups with more increment in 2,000 IU/d than in 1,000 IU/d (46.7 +/- 30.7 vs. 24.0 +/- 21.07 nmol L-1, P = .001). Concentrations of TNF-alpha decreased significantly in group 2,000 (-913.1 +/- 1261.3 ng L-1, P = .01). The cord blood concentration of IL-6 in group 2,000 IU/d, compared with 1,000 IU/d, was significantly lower (25.9 +/- 32.0 vs. 4.6 +/- 1.4 ng L-1, P = .03). The birth sizes including weight, length, and head circumference of the infants of group 2,000 IU/d were significantly higher than the infants' of group 1,000 IU/d. Supplementation with 2,000-IU/d vitamin D3 is more effective than 1,000 IU/d in pregnant women in terms of increasing circulating 25(OH)D, ameliorating pro-inflammatory markers notably TNF-alpha in mother and IL-6 in cord blood, and improving neonatal outcomes including the birth sizes.