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Intrauterine elimination of pyridoxal 5'-phosphate in full-term and preterm infants
1Krankenhaus Düren gemeinnützige GmbH, Düren, Germany.
Insights
Preterm infants eliminate significantly more pyridoxal 5'-phosphate (PLP) in utero than full-term infants, indicating higher fetal vitamin needs. This study quantifies fetal vitamin consumption and maternal requirements during pregnancy.
Area of Science:
- Perinatal Medicine
- Nutritional Biochemistry
- Maternal-Fetal Physiology
Background:
- Pyridoxal 5'-phosphate (PLP) is crucial for fetal development.
- Understanding intrauterine PLP transfer is key to estimating fetal vitamin requirements and maternal needs during pregnancy.
Purpose of the Study:
- To quantify intrauterine elimination of PLP in preterm and full-term infants.
- To estimate fetal vitamin consumption and maternal vitamin requirements during pregnancy.
Main Methods:
- Measured plasma PLP concentrations in maternal, umbilical vein, and umbilical artery blood.
- Calculated umbilical plasma flow using Doppler ultrasonography and hematocrit.
- Determined PLP elimination by the difference in cord plasma PLP and plasma flow.
Main Results:
- Umbilical vein PLP concentrations were ninefold higher than maternal circulation in both infant groups.
- Preterm infants exhibited significantly higher PLP elimination (1.7 nmol/kg/min) compared to full-term infants (0.2 nmol/kg/min).
- Higher plasma flow in preterm infants contributed to their increased PLP elimination.
Conclusions:
- Fetal PLP elimination rates differ significantly between preterm and full-term infants.
- These findings provide insights into fetal vitamin requirements and implications for maternal nutrition during pregnancy.
Abstract:
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.