The study of maternal and fetal cord blood urea nitrogen at delivery in normal pregnancy and toxemia of pregnancy
Chow, S.N.; Chang, F.M.; Chen, H.Y.
Journal of the Formosan Medical Association 87(2): 133-138
1988
ISSN/ISBN: 0371-7682 PMID: 3397712 Document Number: 322577
The maternal blood urea nitrogen (MUN) and fetal cord blood urea nitrogen (CUN) levels were measured simultaneously at parturition in 64 cases of normal pregnancies and 18 cases of toxemia group. Venous blood samples were collected in all of these 82 cases. Blood gas analysis was done on umbilical arterial blood in 36 cases of normal and 14 cases of toxemia group. The correlation coefficients of MUN and CUN were 0.72, 0.88, and 0.81 (all p < 0.001) in normal pregnancy, toxemia of pregnancy and total series, respectively. The high degree of correlation of MUN and CUN implied free placental transfer of urea in both directions. Moreover, both MUN and CUN has significant correlation with birth weight, one-minute Apgar score, pH, pCO2 and base deficit. The MUN and CUN levels were significantly higher in toxemia group than in normal pregnancy. These results suggested that MUN and CUN levels could be used as valuable indicators in managing toxemia of pregnancy and predicting fetal outcome. The levels of CUN were greater than MUN in both normal and toxemia groups. The concentration differences (CUN minus MUN) were found to be 1.7 mg/dl (p < 0.001) and 1.8 mg/dl (p < 0.05) in these two groups, respectively, suggesting a net placental transfer of urea from fetus to mother. These findings implied (1) the higher urea nitrogen of fetus may be derived from the metabolism of amino acids and/or protein; and (2) catabolism of protein and/or amino acids, besides glucose, may be an important source of energy fuel for human fetus in utero.