Despite the well-documented benefits of breast feeding, it is frequently associated with severe jaundice in newborns. When jaundice occurs in breast-fed infants, it tends to have an earlier onset and to be more prolonged. To avoid the development of encephalopathy, most infants with severe hyperbilirubinemia are treated with phototherapy. Tan evaluated the effectiveness of phototherapy in newborns with hyperbilirubinemia.

Otherwise healthy full-term infants with confirmed nonhemolytic neonatal hyperbilirubinemia were eligible for the study. The infants were divided into three groups according to feeding method: the first group consisted of formula-fed infants; the second group consisted of breast-fed infants; and the third group received both types of feeding. Phototherapy was initiated in newborns whose bilirubin concentration was more than 14.9 mg per dL (255 μmol per L), or more than 13 mg per dL (222 μmol per L) within the first 48 hours after birth.

Phototherapy was provided continuously, except during feeding, bathing or provision of nursing care. Bilirubin levels were obtained at baseline and again at 12-hour intervals. Treatment was discontinued when the infant's bilirubin level had decreased to less than 10.8 mg per dL (185 μmol per L) for 24 hours. The shortest duration of phototherapy for any infant was 24 hours. Bilirubin levels were obtained daily for a minimum of two days to ensure that no significant rebound occurred. Hemoglobin and hematocrit levels and infant weight were obtained at baseline and at the end of therapy.

A total of 163 infants were enrolled in the study. Demographic characteristics and bilirubin levels at baseline were similar across groups. The amount of weight loss before the start of therapy was greatest in the breast-fed infants; however, all three groups experienced comparable weight gains during the course of therapy. Phototherapy was highly effective in reducing bilirubin levels in all groups, but the 24-hour decrease and the overall decrease were much less in infants who were breast-fed only. On average, these infants required about 10 more hours of phototherapy than infants in the other two groups. The most rapid response to phototherapy occurred in infants fed both breast milk and formula. Overall, phototherapy was successful in all groups, and no additional therapy was required for rebound hyperbilirubinemia. Notably, jaundice persisted for as long as one month in some of the breast-fed infants, compared with seven to 10 days in the other infants. This impression, however, was subjective, since not all infants were available for long-term evaluation. Even in infants whose random samples of direct bilirubin were obtained, the levels never exceeded 0.6 mg per dL (10 μmol per L).

The author concludes that the severe jaundice that often develops in breast-fed infants requires treatment. Phototherapy was effective in reducing bilirubin levels, but infants who were breast-fed required longer treatment. Supplementing breast milk with formula may improve the response to phototherapy. Therefore, in these infants, interruption of breast feeding does not appear to be necessary.