A new study led by a University College Cork (UCC) researcher and published in a leading international journal has found that delivery by cesarean section is associated with a 23 percent increased risk of Autism Spectrum Disorder (ASD) in childhood.

However, the authors urge caution in interpreting the findings, published in the Journal of Child Psychology and Psychiatry, highlighting the need for more research to further explore the elevated risk.

The review examined the published literature on observational studies in various countries – including the United States, Australia, Canada and Sweden – that investigated the effects of delivery by Caesarean section on ASD.

Overall, the findings suggest that children born by cesarean section have a 23% increased risk of ASD. Researchers also reviewed literature on delivery by cesarean section and attention deficit and hyperactivity disorder (ADHD), but only two studies were included and findings were unclear.

However, the researchers urge caution as the overall risk of ASD, though elevated, remains small. In addition, it is unclear what is driving the association. The relationship between mode of delivery and psychological development is complex, and may involve several contributing factors. Further investigation is needed to understand the interrelationship between environmental factors, such as mode of delivery, and genetic factors with regards to the causes of ASD.

Eileen Curran, lead author, commented: “Given the accelerating rate of cesarean section globally, this finding warrants further research of a more robust quality using larger populations to adjust for important potential confounders and explore potential causal mechanisms.”

Professor Louise Kenny, one of the authors and a practicing obstetrician said: “Parents should be reassured that the overall risk of a child developing ASD is very small and that cesarean section is largely a very safe procedure and when medically indicated, it can be lifesaving.”

The research was jointly coordinated by academics from the Science Foundation Ireland Research Center, the Irish Centre for Fetal and Neonatal Translational Research (INFANT) and the Alimentary Pharmabiotic Center (APC), the National Perinatal Epidemiology Center (NPEC), and the Department of Epidemiology and Public Health at UCC, Ireland. Funding was provided by the Science Foundation Ireland (SFI) funded Center.