Children delivered by caesarean section are more likely to become obese, research suggests.
Harvard experts found children whose mothers underwent the procedure were 15 per cent more likely to be obese by the time they were in their teens.
And the increased risk may persist through adulthood.
In Britain 26 per cent of births are through C-sections. Although in many cases the operation is needed to avoid complications, doctors are increasingly aware it may affect the child in later life.
Experts think this is mainly because babies removed directly from the womb are not exposed to the beneficial bacteria they would get through a natural birth.
Passing through the birth canal primes their immune system and helps prepare their metabolism for the rigours of life, scientists think.
The study, published in the journal JAMA Paediatrics, tracked more than 22,000 people in the US from birth.
The researchers examined the participants when aged between nine and 14, finding those born via C-section were 15 per cent more likely to be obese.
They re-examined the participants again when they were aged between 20 and 28, and found the impact persisted – although it had dropped to 10 per cent.
The difference between C-sections and natural births was even more stark within families. Youngsters born via caesarean delivery were 64 per cent more likely to be obese than siblings who were not.
Senior author Jorge Chavarro said the study provided compelling evidence of a link between childhood obesity and caesarean sections.
He said: ‘Our findings show that risk of obesity in the offspring could be another factor to consider.’
Daily Mail