Maternal bilirubin, cord bilirubin, and placenta function at delivery and the development of jaundice in mature newborns.

Abstract

The study material comprised 213 newborns with a birth weight above 2000 g, and their mothers. At delivery, blood samples were obtained from the umbilical cord and the mother's cubital vein for determination of the transplacental bilirubin gradient and assessment of placental function by means of the HPL concentration in the maternal blood. The HPL concentration showed no relation to the transplacental bilirubin gradient or the umbilical cord bilirubin concentration. Therefore, to the extent that the HPL concentration reflects the rate constants for bilirubin transfer, an increased transplacental bilirubin gradient or an increased cord bilirubin concentration could not be explained by an impaired ability of the placenta to transfer bilirubin. When the infants who became jaundiced were compared with the non-jaundiced, significantly higher transplacental bilirubin gradient (p less than 0.00001), cord bilirubin (p less than 0.00001) and maternal bilirubin values at the time of delivery (p less than 0.03) were found among the jaundiced infants. On the basis of the results it was possible to define subgroups of infants with significantly higher/lower risk of subsequent jaundice.