Bilirubin pigments in the first meconium of newborn infants.

To determine the pattern of excretion of total bilirubin IXa and IXb in the first meconium of newborn infants.First two newborns of varying gestational age were selected every week through random sampling from the neonatal unit. Of the 41 newborn infants selected 8 expired before meconium passage, hence the results are from 33 newborns. Meconium was collected and stored at -20 degrees C, protected by aluminium foil. Samples were defrosted, vortex mixed with equal amount of dimethyl-sulfoxide, centrifuged, and analyzed by HPLC.Unconjugated Bilirubin-IXalpha and -IXbeta were identified and quantitative estimation of Bilirubin-IXa done. Bilirubin-IXb was greater than 50% of the total, in the first meconium of the newborn. Amount of bilirubin excreted in meconium was 29.2 - 90.8 mg [0.051 - 0.155 mmol] per sample of meconium passed. Amount was 9.7 mg/ Kg of body weight in term newborn and 12 mg/kg in preterm.The amount of bilirubin -IXb decreases and bilirubin-IXa increases with increasing gestational age. Newborns with birth asphyxia (BA) had significantly greater quantity of bilirubin in meconium, compared to infants without BA.