NIH Research Matters
November 10, 2008
Earlier Jaundice Treatment Decreases Brain Injury in Preemies
A new study has found that early treatment to prevent severe jaundice in extremely early preterm infants can reduce the rate of brain injury, a serious complication of jaundice.
Jaundice, or yellowing of the skin, is common in newborns. It results from an accumulation of bilirubin, a yellowish substance produced when red blood cells are broken down. Bilirubin is normally removed from the body by the liver. In most infants with jaundice, the yellow color fades after a few days without any ill effects. In some, however, the liver fails to remove bilirubin quickly enough, and potentially toxic levels accumulate—a condition known as hyperbilirubinemia. Untreated, it can cause severe brain injury, leading to cerebral palsy, profound intellectual and developmental disability, blindness and severe hearing loss.
The first line of treatment for hyperbilirubinemia in newborns is phototherapy—exposure to high-intensity light. The light penetrates the skin and converts bilirubin to a less toxic substance that's eliminated through the urine. However, little has been known about treating high bilirubin levels in preterm infants. The new study, appearing in the October 30, 2008, issue of the New England Journal of Medicine, was conducted by researchers in the Neonatal Research Network of NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). The team was led by Dr. Brenda H. Morris, a researcher at the University of Texas Medical School at Houston when the study was conducted.
Almost 2,000 extremely low birth weight infants (less than 1,000 grams, or about 2.2 pounds) were randomly assigned to 2 groups. Infants in the early, or aggressive, treatment group received phototherapy if their bilirubin levels reached 5 milligrams per deciliter—a level that previous studies suggested might result in permanent brain damage. Infants in the conservative treatment group received phototherapy when their levels reached 8 milligrams per deciliter. The infants were then evaluated when they were between 18 and 22 months of age for a range of neurological conditions, including blindness, severe hearing loss, cerebral palsy and a low score on a test of infant cognitive development.
The researchers found that, overall, infants in the aggressive treatment group were less likely to have neurodevelopmental impairment (26%) than those in the conservative treatment group (30%). The results weren't as clear among the smaller infants weighing 501-750 grams (about 1.10-1.65 pounds). Those getting the aggressive treatment were less likely to develop neurodevelopmental impairment than those getting the conservative one. However, they also had a slightly higher death rate, although the difference wasn't large enough to be certain it wasn't due to chance.
These results offer some guidance for doctors and families considering treatment options for jaundice. Early treatment should be considered for larger preterm infants, the researchers say, but for smaller infants, the findings merit caution.
“These are extremely frail infants who may have a number of health problems,” said study co-author Dr. Rosemary Higgins of NICHD. “The bilirubin level shouldn't be considered in isolation. It's just one aspect of an infant's overall health status that needs to be carefully evaluated so that the best treatment decisions possible can be made for that individual.”
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NIH Research Matters is a weekly update of NIH research highlights from the Office of Communications and Public Liaison, Office of the Director, National Institutes of Health.