Breast milk beta-glucuronidase and exaggerated jaundice in the early neonatal period.

Breast-feeding is associated with jaundice in the early neonatal period. Previous work has shown levels of the enzyme beta-glucuronidase in maternal breast milk to be related to infant serum bilirubin on postnatal day 21. Our aim was to establish if there was a correlation between the level of breast milk beta-glucuronidase and the degree of early (first week) neonatal hyperbilirubinaemia. A study of 55 mother and baby pairs showed that breast milk beta-glucuronidase levels had no relationship with the level of infant serum bilirubin between postnatal days 3 and 6. Breast milk beta-glucuronidase does not directly account for the early neonatal jaundice seen in breast-fed babies.