title: Biotin status assessed longitudinally in pregnant women.
abstract: 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.
authors.affiliation: University of Arkansas for Medical Sciences, Department of Pediatrics, Arkansas Children's Hospital, Little Rock 72202, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Mock
authors.forename: D D
authors.initials: DD
authors.lastname: Stadler
authors.forename: S L
authors.initials: SL
authors.lastname: Stratton
authors.forename: N I
authors.initials: NI
authors.lastname: Mock
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001710:Biotin / Q000031:analogs & derivatives / Q000097:blood* / Q000378:metabolism / Q000652:urine; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D008137:Longitudinal Studies; D011247:Pregnancy / Q000097:blood* / Q000378:metabolism / Q000652:urine; D012189:Retrospective Studies; D014631:Valerates / Q000652:urine
chemical_list: D014631:Valerates; C002143:bisnorbiotin; C004961:beta-hydroxyisovaleric acid; D001710:Biotin; C017072:D-biotin-d-sulfoxide