Researchers in Denmark believe they may have uncovered a link between jaundice in full-term newborns and the development of certain psychological development disorders, including autism, according to a report published in the November 2010 issue of the journal Pediatrics.
To reach their findings, researchers looked at data on the 733,826 live births in Denmark between 1994 and 2004. Over 35,000 newborns were diagnosed with neonatal jaundice, a fairly common illness in babies that usually goes away within a week of birth. As researchers continued to track child health statistics, autism was eventually diagnosed in 577 cases. Among autistic children, almost 9 percent had jaundice as newborns, compared with 3 percent of other children—a 67 percent increased risk for the disorder.
Researchers also note that autism risk was higher if the mother had had previous children, or if the child was born between October and March. Increased risk for autism among newborns with jaundice disappeared if the child was a firstborn child or was born between April and September. Seasonal differences may be due to different levels of exposure to daylight, which has an effect on jaundice, researchers speculate. The difference in risk in firstborn versus subsequent children could be due to different levels of antibodies in women who have had multiple pregnancies, or it could reflect different levels of access to healthcare in the first days after delivery. As noted in the study, Danish women with healthy term newborns who have already had children are discharged soon after delivery, perhaps before a diagnosis of jaundice can be made.
Worried? Try not to be, health experts advise. "Jaundice is almost always harmless ... The evidence for an association (with autism) is weak and inconsistent and evidence for causality nonexistent," says Dr. Thomas Newman, a pediatrician and epidemiologist at the University of California at San Francisco who studied the same topic and found no link, in an interview with ABC News.
As Newman points out, the study lacked data on severity of jaundice, which involves having elevated levels of bilirubin in the body. Also, no increase for autism was found among preterm infants with jaundice.
Bilirubin is yellowish pigment created as the body recycles old red blood cells. It is processed by the liver; during pregnancy the mother's liver handles the job, but after birth it can sometimes take a newborn's liver a few days to successfully take over the task. Mild jaundice may cause a yellowish-orange tinge to the skin. Newborns are typically examined for jaundice before leaving the hospital, and it usually disappears within a week or two without treatment. Exposing babies to direct sunlight or using medically supervised UV light therapy are usually effective in treating jaundice.