C-sections DON'T cause autism, scientists say

Giving birth via Caesarean section does not make a child more likely to be autistic, scientists have established.

Previous research has found a statistical link between C-sections and a child being on the autistic spectrum.

But the latest findings suggest that the circumstances in which a child is born is unlikely to actually cause autism.

The study, published in the medical journal JAMA Psychiatry, instead suggests that an autistic child is more likely require a Caesarean because of some unknown genetic or environmental factor.

It was at the Irish Centre for Foetal and Neonatal Translational Research in Cork.

There, researchers re-examined data that had previously shown children born by Caesarean section were 21 per cent more likely to be diagnosed with autism.

The team went further than the initial analysis and looked at whether the autistic children had siblings who were also autistic.

A large factor causing autism is thought to be in someone’s genes.

When the scientists analysed data from the children’s brothers and sisters, they were able to estimate the extent of the genetic factor. 

By taking this into account, the statistical association to the Caesarean-section disappeared.

Study leader Dr Ali Khashan said: ‘Because the association between birth by Caesarean section and autistic spectrum disorder did not persist in the sibling control analysis, we can conclude that there is no causal association.

‘It is more likely that birth by Caesarean section is related to some unknown genetic or environmental factor that leads to increased risk of both Caesarean section and autistic spectrum disorder.’
The findings were welcomed by British experts.

Professor Andrew Whitelaw of the University of Bristol said: ‘This is an important and robust study.

'The fact that this is the largest study by a long way (nearly 2.7 million children born in Sweden, a country with all its residents on a database with a personal number that follows them through all official interactions), gives robustness. 

'Furthermore, databases in Sweden can be linked over many years, across generations, and between siblings while still protecting personal confidentiality. 

'Also, the observed association between Caesarean section and ASD could be adjusted to according to whether a sibling had ASD or not. 

For many years there has been strong evidence that there is a genetic contribution to ASD. When adjustment was made for sibling ASD, there was no association between Caesarean section and ASD. 

'This is good evidence that Caesarean section does not cause ASD.' 

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