Protein metabolism in the small for gestational age newborn in relation to the severity of fetal malnutrition

: The daily nitrogen balance, the amino acid concentrations in serum and urine, and the bile acid concentrations in the serum on the eighth day of life were estimated in newborn infants small for gestational age with different degrees of fetal malnutrition. The amino acid concentrations in urine and serum as well as the total nitrogen losses by urine increase in dependence on the severity of fetal malnutrition. In addition the bile acid concentrations were elevated whereas the urea concentrations in serum remained unchanged. These results point to a deranged liver function which depends on the degree of fetal malnutrition. These special metabolic conditions have to be considered in the nutrition of such infants. The bile acid concentrations seem to be an efficient parameter to estimate this metabolic situation.