Babies born through Caesarean section are more likely to develop autism, a new study claims.

In a report published today, academics warn the increasingly frequent birth method heightens the risk of the disorder by 23 per cent.

However, they urge caution about the findings and have stressed more research is needed.

Professor Louise Kenny, one of the authors and a practising obstetrician, said the link between C-sections and children developing Autism Spectrum Disorder (ASD) remained unclear.

"Parents should be ­reassured that the overall risk of a child developing ASD is very small and that Caesarean section is largely a very safe procedure and, when medically indicated, it can be lifesaving," she said.

The study was carried out by University College Cork and has been published in the Journal of Child Psychology and Psychiatry. It reviewed ­existing findings from ­studies on C-section and ASD in a number of countries including the United States, Australia, Canada and Sweden.

Researchers also looked for any links between the surgical delivery of a baby and attention deficit and hyperactivity disorder, but there were only two studies to review and their findings were unclear.

Eileen Curran, lead author of the report, said the relationship between the type of delivery used in childbirth and psychological development was complex.

"Given the accelerating rate of Caesarean 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," she said.