THE MAJORITY of studies in the literature report levels of bilirubin in premature infants during the first week of life, but relatively little information is available concerning bilirubin levels thereafter. "Physiologic jaundice" tends to be of longer duration in low birth weight than in term infants1; in addition, bilirubin levels tend to be higher and to remain so for a longer period.
A feeding study (R. G. P., A. J. R., M. M. D., and P. Phitaskspraiwan, unpublished data) carried out in the low birth weight nursery of Jefferson Davis Hospital afforded an opportunity to evaluate the range of "normal values" in a given population and to follow serial bilirubin levels in infants of low birth weight (2,000 gm [4 lb 6 ounces] or less) throughout the first four weeks of life.
The incidence of low birth weight infants in our nursery population has been in the range of