Biotin status assessed longitudinally in pregnant women

J Nutr. 1997 May;127(5):710-6. doi: 10.1093/jn/127.5.710.


This study assessed biotin nutritional status longitudinally during pregnancy as judged by urinary excretion of biotin and biotin metabolites and by serum concentration of biotin. 3-Hydroxyisovaleric acid excretion was also assessed because increased excretion of that acid reflects decreased tissue activity of the biotin-dependent enzyme, methylcrotonyl-CoA carboxylase. Thirteen women provided untimed urine samples during both early and late pregnancy. Twelve nonpregnant women served as controls. Biotin and metabolites were determined by a combined HPLC/avidin-binding assay. 3-Hydroxyisovaleric acid was determined by gas chromatography/mass spectrophotometry. Significance of changes from early to late pregnancy was tested by paired t test; to compare nonpregnant controls with early and late pregnancy, ANOVA was used. During early pregnancy, biotin excretion was not significantly different than controls; however, 3-hydroxyisovaleric acid excretion was significantly increased relative to controls (P < 0.0001) and was greater than the upper limit of normal in 9 of 13 women. From early to late pregnancy, biotin excretion decreased in 10 of 13 women (P < 0.01); by late pregnancy, biotin excretion was less than normal in six women. During late pregnancy, 3-hydroxyisovaleric acid remained significantly increased relative to controls (P < 0.0001). Serum concentrations of biotin were significantly greater than those of controls during early pregnancy (P < 0.0001) and decreased in each woman from early to late pregnancy (P < 0.0001). These data provide evidence that biotin status decreases during pregnancy.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Analysis of Variance
  • Biotin / analogs & derivatives
  • Biotin / blood*
  • Biotin / metabolism
  • Biotin / urine
  • Biotransformation
  • Chromatography, High Pressure Liquid / methods
  • Female
  • Gas Chromatography-Mass Spectrometry / methods
  • Humans
  • Longitudinal Studies
  • Pregnancy / blood*
  • Pregnancy / metabolism
  • Pregnancy / urine
  • Retrospective Studies
  • Valerates / urine


  • Valerates
  • bisnorbiotin
  • beta-hydroxyisovaleric acid
  • Biotin
  • D-biotin-d-sulfoxide