A study published in this month's journal, Pediatrics, has found an association between newborn jaundice and autism. Researchers looked at the Denmark birth registry of all babies born over a period of 10 years (1994-2004), which totaled about 733,000 children.
The full term babies who were diagnosed with jaundice (yellowing of the skin which I will explain further) had a significantly greater risk of being diagnosed with an autism spectrum disorder (ASD) later in life. Interestingly, the subset of children whose birthdays fell in the winter months (October through March) had higher odds of having an autism spectrum disorder. And, babies who were NOT the firstborn were also more likely to have an ASD.
The researchers cannot explain this phenomenon by the data. But they speculated that the winter months either put these babies at risk for having more winter viral infections or that there was less sunlight, leading to an increased risk of becoming jaundiced. And, babies whose moms had other kids were more likely to either be discharged home from the hospital sooner (thus increasing the chances of missing early treatment for jaundice) or the moms had more antibodies to a baby's blood which is a set up for jaundice.
What is jaundice, anyway? Well, it is a temporary yellowing of the skin caused by a deposit of pigmented body waste called bilirubin. Newborns frequently experience jaundice in the first few days of life because they aren't too interested in eating so they aren't pooping (which is where that bilirubin body waste is supposed to come out). And, their liver isn't working at full efficiency yet, which helps to break down the bilirubin. For most newborns, a little jaundice isn't considered a big deal- in fact, it's normal. But nurses and doctors watch closely to be sure that bilirubin levels do not shoot up too high and exceed the skin's ability to contain it. Once the skin is saturated, bilirubin can collect in the brain and cause permanent neurologic damage. We've known for a long time that really high bilirubin levels cause intellectual disability and cerebral palsy. Finding an association with autism is new.
So, considering that 60% of babies who are born full term and 80% of premature babies develop jaundice, this study certainly peaked my interest. What is important to note is that the Denmark birth registry data does not specify how severe the jaundice was (which we can easily test for with a simple blood test) and whether or not babies who were diagnosed with jaundice were treated and how soon they were treated. This information is very important in knowing what to make of this data and if healthcare providers need to be more aggressive about treating jaundice.
Bottom line: More research is needed to see if jaundice is truly a risk factor that can cause autism. And if there is an association, do we need to change our current standard of treatment? So what's a new parent to do? Keep a close eye out for jaundice in your newborn and notify your healthcare provider if you see it.