An induced labour does not appear to increase the risk of autism in babies, a new study has revealed.

Initial research found that 3.5 per cent of babies born after induction were diagnosed with autism by age 20, compared to just 2.5 per cent of infants born naturally.

While this suggests that there is around a 19 per cent greater risk of autism after induced labour, researchers found contradicting results when looking at sibling pairs.

When one baby arrived after induction and another did not, there was no visible link between induced labour and risk of autism, the report suggests.

The findings oppose a large U.S. study that had linked induced labour with an increased risk of autism in 2013.

From a pool of nearly 700,000 siblings, the increased risk of autism actually stemmed from factors that lead to an induced labour, such as genetics or medical issues experienced by mothers.

In an email to Reuters, Dr Anna Sara Oberg, of Harvard University in Boston, said: “The association observed between unrelated individuals may be a result of confounding factors, and not a causal effect of labor induction on the risk of autism spectrum disorder”.

Dr Oberg’s team had found that induced labour was more common in older mothers, or those who were obese, hypertensive, or diabetic.

Education level, country of origin and smoking status in early pregnancy, however, did not appear to have an impact on whether they would have an induced labour.

Dr. Daniel Coury, a researcher at Ohio State University in Columbus and Nationwide Children’s Hospital, said the study had widened the field of autism research.

He said: “The odds are very positive that the product of an IVF pregnancy or an induced labor is going to be a healthy child.

“The great majority of children with autism have not been the product of an induced labor; we still don’t know all the causes of autism.”