URINARY D-GLUCARIC ACID EXCRETION IN IDIOPATHIC NEONATAL JAUNDICE

Objective. To determine the extent to which immaturity of hepatic micr osomal enzyme activity might contribute to physiological jaundice. Met hods, Urinary excretion of D-glucaric acid, expressed in mu mol glucar ic acid/mmol creatinine, was measured in 122 Chinese full-term healthy newborn babies during the first five days of life. Among the 122 babi es, 22 were born by normal spontaneous delivery at the British Militar y Hospital and 100 were born by caesarean section at the Prince of Wal es Hospital. Results. In all babies the excretion of D-glucaric acid w as highest on the first day of life and gradually decreased over the f ollowing 5 days. Five babies born by spontaneous delivery and six babi es born by caesarean section developed jaundice during the study perio d. The excretion of D-glucaric acid in the jaundiced babies was signif icantly higher on the first two days than in the non-jaundiced babies. Conclusions, D-glucaric acid excretion was increased in jaundiced new born babies in the first few days of life. This finding does not indic ate less liver microsomal enzyme activity in the jaundiced babies comp ared to those non-jaundiced. On the contrary, it suggests that in idio pathic neonatal jaundice compensatory mechanisms might operate from a very early stage to excrete a higher bilirubin load that might be pres ent through haemolysis.