Breast milk β‐glucuronidase and prolonged jaundice in the neonate

Breast milk samples from mothers of breast-fed, healthy, term newborns with unexplained prolonged jaundice were analyzed for β-glucuronidase activity. Mean enzyme activity was 75.7 ± 34.5 modified Sigma units/ml in the breast milk samples ingested by the study group of jaundiced babies (n= 25) and 82.2 ± 40.1 modified Sigma units/ml in the samples ingested by the control group of non-jaundiced babies (n = 20) (p > 0.05). Enzyme activities at 2, 3 and 4 postnatal weeks were 101.0 ±39.9, 66.0 ± 20.7 and 57.0 ± 22.4 modified Sigma units/ml in the study group and 87.9 ±36.1, 58.5 ± 15.0 and 88.3 ±49.1 modified Sigma units/ml in the controls. The differences were not statistically significant (p > 0.05). We conclude that breast milk β-glucuronidase activity may be a contributory factor, in the presence of other variables, in hyperbilirubinemia but it is neither the main nor the only cause of prolonged jaundice in neonates.