The effect of a maternal infusion of amino acids on umbilical uptake in pregnancies complicated by intrauterine growth restriction.
OBJECTIVE
To establish whether, in human pregnancies complicated by intrauterine growth restriction (IUGR), the maternal intravenous infusion of amino acids can increase fetal amino acid concentrations and umbilical uptake.


METHODS
Before elective cesarean delivery, a solution of amino acids was infused into a maternal vein in 8 patients with pregnancies complicated by IUGR (experimental group). At cesarean delivery, maternal, umbilical venous, and arterial blood samples were obtained. Ten comparable IUGR pregnancies were compared with those in the experimental group.


RESULTS
In the experimental group, all maternal amino acid concentrations were increased significantly. In the umbilical vein, valine, methionine, isoleucine, leucine, phenylalanine, arginine, serine, glycine, and proline concentrations were elevated. Umbilical venoarterial differences of amino acid per mole of oxygen for leucine, isoleucine, methionine, arginine, glycine, serine, and proline were elevated but not for lysine, histidine, threonine, valine, and phenylalanine.


CONCLUSIONS
In pregnancies complicated by IUGR, increasing the maternal concentration of amino acids leads to an increased umbilical uptake of some of the amino acids to the fetus. There was no evidence of a change in the uptake of 3 essential amino acids: lysine, histidine, and threonine.
Ronzoni
Stefania
S
Department of Obstetrics and Gynecology, University of Milano, Italy.
Marconi
Anna Maria
AM
Paolini
Cinzia Lucia
CL
Teng
Cecilia
C
Pardi
Giorgio
G
Battaglia
Frederick C
FC
D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage / Q000378:metabolism*; D005260:Female; D005317:Fetal Growth Retardation / Q000378:metabolism*; D006801:Humans; D007262:Infusions, Intravenous; D011247:Pregnancy; D014470:Umbilical Cord / Q000378:metabolism*
D000596:Amino Acids