The relationship of breast feeding to third-day bilirubin levels.

The purpose of this study was to determine the relationship of feeding method to serum bilirubin levels on the third day of life. Two hundred eighty-one apparently healthy full-term neonates had third-day bilirubin levels drawn between 58 and 82 hours of age. Mean serum bilirubin levels were 5.6 mg/dL for formula-fed, 6.9 mg/dL for mixed-fed, and 7.5 mg/dL for breast-fed infants. The difference was statistically significant (P less than .01) between the formula-fed and breast-fed groups. Breast-fed infants lost more weight by the third day than formula-fed infants (mean weight loss 180 g for breast-fed infants, 100 g for formula-fed infants). A third-day bilirubin levels among the feeding groups were then compared using an analysis of covariance with weight loss as the covariate. By this method, type of feeding was still a significant predictor of third-day bilirubin levels (P = .04) as was weight loss (P = .03).