The effects of season and stage of pregnancy on 25-hydroxy-vitamin D levels in pregnant women in Madrid.
The influence of seasonal variations and gestation on 25(OH)D3 levels was studied in a group of women from Madrid, Spain, at different stages of pregnancy, during March and September. The objective was to observe the incidence of this climate and dietary factors. No variations were found in serum concentration of the metabolite throughout pregnancy in comparison with the controls, in either March or September. 25(OH)D3 values decreased after winter in both groups of women, although mean values were consistently higher than 16 ng/ml.