Maternal-fetal-infant dynamics of the C3-epimer of 25-hydroxyvitamin D

Dana Bailey, Nandita Perumal, Mehrdad Yazdanpanah, Abdullah Al Mahmud, Abdullah H. Baqui, Khosrow Adeli, Daniel E. Roth

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Background: Poor vitamin D status (i.e. low serum 25-hydroxyvitamin D (25(OH)D)) has been associated with adverse clinical outcomes during pregnancy and childhood. However, the interpretation of serum 25(OH)D levels may be complicated by the presence of the C3-epimer of 25(OH)D. We aimed to quantify C3-epi-25(OH)D3 in pregnant women and fetuses, to explore the relationship of the C3-epimer between maternal and cord samples, and to establish whether infant C3-epimer abundance is explained by prenatal formation. Methods: In a sub-study of a randomized trial of prenatal vitamin D3, 25(OH)D3 and C3-epi-25(OH)D3 were quantified by LC-MS/MS in 71 sets of mother-fetus-infant serum samples, including maternal delivery specimens, cord blood, and infant specimens acquired at 3-28weeks of age. Results: Without supplementation, median concentrations of C3-epi-25(OH)D3 were higher in infants (6.80nmol/L) than mothers (0.45nmol/L) and cord blood (0nmol/L). However, there was substantial variation such that C3-epi-25(OH)D3 accounted for up to 11% (maternal), 14% (cord), and 25% (infant) of the total 25(OH)D3. Supplemental vitamin D3 significantly increased maternal-fetal C3-epi-25(OH)D3, and was a preferential source of C3-epi-25(OH)D3 compared to basal vitamin D, possibly due to C3-epi-cholecalciferol in the supplement. Multivariate regression did not suggest transplacental transfer of C3-epi-25(OH)D3, but rather indicated its generation within the fetal-placental unit from maternally-derived 25(OH)D3. Neither maternal nor fetal C3-epi-25(OH)D3 is accounted for the relatively high concentrations of infant C3-epi-25(OH)D3, suggesting rapid postnatal generation. Conclusions: C3-epi-25(OH)D3 is present in some pregnant women and fetuses, but does not appear to be efficiently transferred transplacentally. High C3-epimer concentrations in infancy are probably due to postnatal formation rather than fetal stores.

Original languageEnglish (US)
Pages (from-to)816-822
Number of pages7
JournalClinical Biochemistry
Issue number9
StatePublished - Jun 2014


  • 25-Hydroxyvitamin D
  • C3-epi-25-hydroxyvitamin D
  • Cord
  • LC-MS/MS
  • Maternal

ASJC Scopus subject areas

  • Clinical Biochemistry


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