Balance of amino acids in the pregnant human uterus at term.

The nutritive and metabolic state of the human uterus at term is evaluated by measuring the uptake and release of amino acids. The subjects are ten healthy women with normal pregnancy undergoing elective caesarean section at term, before onset of labour. Free amino acids in arterial (radial artery) and venous (plexus of the uterine and ovarian veins) blood are determined and arteriovenous (AV) differences in each amino acid across the uterus are calculated. Generally the AV differences are negative, i.e. uterus at term releases amino acids in most cases. The human pregnant uterus at term is characterized by a release of amino acids rather than uptake. This indicates that they are in excess and are not needed in anabolic processes or as a fuel, even when the uterine tissue at term is supposed to be preparing for its grand performance, i.e. the delivery.