Intrauterine elimination of pyridoxal 5'-phosphate in full-term and preterm infants

Gerold Link, Janos Zempleni

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


This study addressed the intrauterine elimination of pyridoxal 5'- phosphate (PLP) in 15 preterm and 31 full-term infants, thereby providing estimates of fetal vitamin consumption as well as maternal vitamin requirements during pregnancy. Elimination was calculated as the difference in the plasma PLP concentration between umbilical vein and umbilical artery times the umbilical plasma flow. Plasma flow in the umbilical vein was calculated from pulsed Doppler ultrasonographic determination of blood flow and from the hematocrit value. Plasma PLP concentrations were assayed in maternal and umbilical veins and the umbilical artery; PLP concentrations were similar in preterm and full-term infants (P > 0.05). In both groups of infants the PLP concentration in the umbilical vein (preterm: 100.3 nmol/L; full-term: 63.9 nmol/L) was ninefold higher than in maternal circulation (P < 0.001). In full-term infants, PLP concentrations in maternal and umbilical veins correlated weakly (r = 0.358, P < 0.05), but no significant correlation was found in the preterm group (P > 0.05). The arteriovenous concentration gradient of PLP in cord vessels was higher in preterm infants (15.0 nmol/L) than in full-term infants (2.1 nmol/L), but the difference between groups was not significant (P > 0.05). Preterm infants eliminated 1.7 nmol PLP · kg- 1 · min-1 in utero, whereas full-term infants eliminated 0.2 nmol PLP · kg-1 · min-1 (P < 0.05). The significantly higher plasma flow in preterm infants (116 mL · min-1 · kg-1) compared with full-term infants (78 mL · min-1 · kg-1) contributed to the higher PLP elimination in preterm infants.

Original languageEnglish (US)
Pages (from-to)184-189
Number of pages6
JournalAmerican Journal of Clinical Nutrition
Issue number2
StatePublished - Aug 1996
Externally publishedYes


  • Pyridoxal 5'-phosphate
  • full-term infants
  • intrauterine supply and elimination
  • preterm infants

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics


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