Maternal and fetal amino acid concentrations in normal pregnancies and in pregnancies with gestational diabetes mellitus

Objective: This study was undertaken to compare amino acid concentrations in normal pregnancies and pregnancies with gestational diabetes (GDM), a condition associated with altered fetal growth. Study design: Maternal and fetal amino acids were evaluated by high-performance liquid chromatograph at the time of delivery in 16 normal and 17 GDM pregnancies. Fetal weights were not different, but placental weights were significantly higher and fetal/placental weight ratios were significantly lower in GDM compared with normal. Results: Ornithine was significantly increased in GDM mothers. In umbilical vein and artery of GDM significant increases were observed for valine, methionine, phenylalanine, isoleucine, leucine, ornithine, glutamate, proline, and alanine, whereas glutamine was significantly decreased. Conclusion: Placental amino acid exchange is altered in GDM pregnancies. Moreover, the changes observed for glutamine and glutamate in the umbilical samples suggest that in GDM the fetal hepatic production of glutamate is increased, likely as a consequence of the endocrine changes in the fetal compartment.