Longitudinal changes in vitamin D concentrations during pregnancy among Brazilian women

Abstract Number Theme Presentation Type Cover Approved
0594 Prevalence and risk factors for micronutrient status(deficiency, overload) Poster Not Approved


Abstract Content


To estimate the prevalence of vitamin D inadequacy and to characterize the physiological changes in 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxivitamin D [1,25(OH) 2D] across healthy pregnancy.


A cohort of 229 apparently healthy pregnant women was followed between 5th-13th, 20th-26th and 30th-36th gestational weeks. The 25(OH)D (nmol/L) and 1,25(OH)2D (pmol/L) were measured by LC-MS/MS, method considered the gold standard. The vitamin D status in the first trimester was based on 25(OH)D categorized as inadequate (<75 nmol/L) and adequate (=75 nmol/L) according to the U.S. Endocrine Society. Statistical analyses included longitudinal linear mixed-effects models reporting regression coefficient (ß) and 95% confidence intervals


The mean age was 26.6 year and pre-pregnancy BMI = 25 kg/m2 was 40.2%. The prevalence of vitamin D inadequacy was high during the first trimester, second and third trimesters (70.4%, 41.0% and 33.9%, respectively). Women who started the study during winter presented a higher prevalence of 25(OH)D inadequacy (88.2%) compared to those who started in summer (54.8%) or autumn (59.6%). There was a mean increase in 25(OH)D (ß= 0.869; 95% CI: 0.723-1.014; P<0.001) and 1,25(OH)2D nmol/L (ß)= 3.878; 95% CI, 3.136-4.620; P<0.001) concentrations during pregnancy.


The prevalence of vitamin D inadequacy was high across pregnancy. A seasonal variation was observed. The concentrations of 25(OH)D and 1,25(OH)2D increased across trimesters.

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