Diurnal variation in serum bilirubin concentrations in infants with neonatal jaundice.

We investigated whether there are independent intradaily changes in bilirubin levels in neonates. Healthy term newborn infants (n = 124) with neonatal jaundice bilirubin >/t171 mmol/L (10mg/dl) were studied for at least 3 consecutive days. Starting from the second day of life, consistent intradaily changes were observed in bilirubin levels (morning levels were greater than evening levels; p < 0.001), and body weight steadily increased. This diurnal variation in bilirubin levels should be considered in the follow-up and treatment of neonatal jaundice.