Even in Vitamin D Deficiency 1, 25 Dihydroxyvitamin D3 Level Is Normal in Pregnant Women

  Vitamin D deficiency is a controversial issue in pregnant women. The 1,25 dihydroxyvitamin D3 level is higher in pregnant than non-pregnant women. This study aimed to investigate the 1,25 di-hydroxyvitamin D3 status in vitamin D deficient pregnant women at the first trimester. This study was conducted during December 2011 and April 2012 in 2 hospitals of Istanbul, Turkey. Pregnant women who attended for the regular examination on the 12th gestational week were randomly assigned. They were divided into 2 groups including vitamin D deficient (vitamin D <30 ng/mL) and vitamin D optimal (vitamin D ≥30 ng/mL). Serum 25 hydroxyvitamin D3, 1,25 dihydroxyvitamin D3, fibroblast growth factor 23, calcium, phosphate, urinary calcium, and urinary phosphorus levels were measured. After exclusion of fourteen pregnant women due to inconvenient serum samples, the mean serum 25 hydroxyvitamin D3 level of one hundred sixty outpatient pregnant women was 10.8 ± 16.2 ng/mL. Totally, 132 (85.0%) of these women were vitamin D deficient (25 hy-droxyvitamin D3 level less than 30 ng/mL). Serum 1,25 dihydroxyvitamin D3 and urinary calcium levels were higher in vitamin D deficient than vitamin D optimal group. Even under severe vitamin D deficiency, the 1,25 dihydroxyvitamin D3 level was high in pregnant women. Active vitamin D status was not compatible with the 25 hydroxyvitamin D3 level in vitamin D deficient pregnant women at the first trimester.