Researchers from Aarhus University in Denmark and the University of California found that full-term children who had jaundice within a few days or weeks of birth had a 50 to 88 per cent greater risk of developing psychological development disorders, compared with other babies.
Babies born between October and March who had developed jaundice also showed a greater risk of autism. The researchers suggested this could be because of reduced exposure to daylight and the increased number of infections during the winter period.
The risk of an autism diagnosis increased if the child was born between October and March but was no greater if the child was born between April and September, the study said.
Similarly, babies with jaundice whose mothers had given birth to one or more children previously were more likely to be autistic. This could be attributed to a woman's higher level of antibodies or the reduced level of care she may have received, said the authors.
The researchers looked at data from the Danish Medical Birth Register for all children born between 1994 and 2004. They also considered the age of parents, citizenship, exposure to smoke during pregnancy, a child's birthweight and their Apgar score, a classification of the health of a newborn.
Dr Gina Gomez de la Cuesta, action research leader at the National Autistic Society, said, 'The causes of autism are still being investigated, and large-scale studies of this kind can provide a useful insight. While the findings seem to suggest a link between neonatal jaundice and autism in some children, this is by no means conclusive. Any research which considers potential causes can understandably prompt concern among parents, so it is important that appropriate information and support is available.'
Further information: Neonatal Jaundice, Autism, and Other Disorders of Psychological Development is published in the journal Paediatrics.