Newborns diagnosed with jaundice may have a higher risk of developing a mild form of autism in childhood, new research suggests, a finding that could provide new clues on the causes of autism, which affects as many as 1 in every 110 children born in the United States.
Jaundice, a yellowing of eyes and skin, is common in newborns, and usually goes away on its own within a week after birth. It's caused by the buildup of bilirubin, a substance normally produced by the body as it breaks down unneeded red blood cells. But too much bilirubin not only leads to jaundice, it can be toxic to neurons, causing cerebral palsy, deafness, and brain damage. So it makes sense that jaundice, and bilirubin, could also be involved in autism spectrum disorders.
Jaundice has been suspected in autism before, but it hasn't been the subject of much research. This new study is huge—based on the medical records of 733,826 children, all born in Denmark. A gigantic population like that makes it easier for the scientists to study small effects. They found that children who got jaundice soon after birth were 56 percent more likely to be diagnosed with "pervasive developmental disorder," a mild form of autism, and nearly twice as likely to have any form of psychological developmental disorder in childhood.
Interestingly, children born in winter months were also more likely than those born in the summer to be diagnosed with both jaundice and autism, perhaps because exposure to sunlight helps the body clear excess bilirubin, the researchers speculate. More pieces of the puzzle: Children born full term were more likely to have both jaundice and autism diagnoses, as were children who were not firstborns. The research was conducted at Aarhus University in Denmark.
Of course, most children who get jaundice as newborns never have autism or other developmental disorders. Clearly, it will take a lot more time and effort for scientists to figure out if jaundice really is a trigger for some cases of autism, or if the link is mere coincidence.
Meantime, parents can do their best to reduce any possible risk by ensuring newborns are monitored for jaundice, and are treated properly if diagnosed with the disorder. The National Institutes of Health recommends the following:
- All new babies should be checked for signs of jaundice every 9 or 12 hours in their first day of life.
- A newborn who looks jaundiced, with yellow eyes and skin, in the first day after birth should be immediately screened for bilirubin levels with a skin or blood test. (Many hospitals routinely perform bilirubin screenings on newborns.)
- Jaundiced babies should be kept well-fed with breast milk or formula. The body disposes of excess bilirubin in stool.
- For babies with very high levels of bilirubin, consider phototherapy, in which a bright light is used to help break down bilirubin in the skin.
The vast majority of babies with jaundice get better within two weeks without any treatment, but the known complications from high bilirubin levels can be devastating: cerebral palsy, deafness, and brain damage. If you think your baby looks jaundiced, make sure the hospital or pediatrician does the necessary tests.