Urinary urea nitrogen ratios: further observations.

The urea nitrogen/total nitrogen (UN/TN) and urea nitrogen/creatinine nitrogen (UN/CN) ratios in urine were compared as indicators of recent protein intake in pregnant women. The UN/CN ratio more accurately predicted recent dietary protein levels. The effects of other factors, including diabetes mellitus, on the UN/CN ratio were investigated. The UN/CN ratio is a simple and effective means of determining recent protein intake in the pregnant woman.