Effect of feeding type on the efficacy of phototherapy.

OBJECTIVE The objective of this study was to assess the efficacy of phototherapy for nonhemolytic hyperbilirubinemia and rebound bilirubin levels in breast-fed newborns as compared with mixed-fed (breast milk and formula) newborns. STUDY DESIGN/SETTING Prospective study of effects of feeding type on response to phototherapy in newborns. METHODS The subjects were 53 full-term healthy newborns with nonhemolytic hyperbilirubinemia [defined as total serum bilirubin 12 mg/dL (205.2 micromol/L) in the first 48 hours of life or 15 mg/dl (256.5 micromol/L), on subsequent days]. Groups were formed according to type of feeding. Group 1 consisted of 28 breast-fed newborns and group 2 consisted of 25 mixed-fed newborns. Phototherapy was terminated when total serum bilirubin concentration fell to 14 mg/dL (< 239.4 micromol/L). Rebound bilirubin measurements were obtained 24 hours after phototherapy ended. RESULTS The groups were comparable with respect to age at the start of phototherapy. The amount of weight loss (relative to birth weight) recorded at the start of phototherapy was significantly greater in group 1 than in group 2 (8.1+/- 3.9% vs. 5.4+/- 2.6% p = 0.004). The duration of phototherapy was significantly longer in group 1 than in group 2 (38.6+/- 12.6 h vs. 26.8+/- 9.4 h; P < 0.001). The 24-hour rate of decrease in bilirubin concentration in group 2 was significantly higher than that in group 1 [5.4+/- 2.2 mg/dL/d (92.3+/-37.6 micromol/L/d) vs. 4+/- 1.3 mg/dL/d (68.4+/- 22.2 micromol/L/d); p = 0.01]. The overall rate of decrease in bilirubin concentration in group 1 was significantly lower than that in group 2 [0.16+/- 0.05 mg/dL/h (2.73+/- 0.85 micromol/L/h) vs. 0.22+/- 0.09 mg/dL/h (3.76+/- 1.53 micromol/L/h); p = 0.01]. There was no significant difference between the two groups with respect to rebound bilirubin concentration (P = 0.184). CONCLUSION Phototherapy effectively reduced bilirubin levels in breastfed newborns with hyperbilirubinemia, but these patients show significantly slower response to this treatment than mixed-fed newborns.