"These are reassuring results" said Thomas B. Newman, MD, MPH, professor of pediatrics and biostatistics at UCSF and the lead investigator of the study. "Our research shows that when severe jaundice is detected and treated properly, we can prevent long-term neurological problems." The study appears in the May 4, 2006 issue of NEJM.
Jaundice is a common condition in newborns. It refers to the yellow color of the skin and eyes caused by excess levels of bilirubin in the blood. Bilirubin is produced by the normal recycling and replacement of red blood cells. In adults the liver processes the bilirubin, but in newborns the liver is still immature and often is unable to break bilirubin down fast enough, so levels build up. In a newborn the bilirubin rises rapidly in the first few days after birth, peaking below 15 milligrams per deciliter (mg/dL) in about 90 percent of babies. Levels of 30 mg/dL or more can lead to a condition called kernicterus, which can cause deafness, cerebral palsy, brain damage or even death.
Kernicterus is rare, however, and little research has been done on infants who have bilirubin levels that are elevated, but below the 30 mg/dL mark. In this study, researchers compared 140 infants with bilirubin levels of between 25 mg/dL and 30 mg/dL, a level reached by only about 1 in 700 newborns, to more than 400 control infants.
The researchers followed the children up to five years of age, measuring IQ, performing neurological exams and interviewing parents. They found no significant difference between jaundiced and control newborns in IQ or behavior, or in the proportion of children with abnormal neurological examinations, or with neurological diagnoses.
The usual treatment for infants with elevated bilirubin levels is phototherapy. The baby is exposed to bright light that is absorbed through the skin, altering the bilirubin and making it easier for the baby's liver to get rid of it.
"Having a child in the hospital receiving phototherapy can be frightening for parents," said Gabriel J. Escobar, MD, research scientist, Kaiser Permanente Division of Research. "This study should assuage some of those families' concerns."