Babies born by caesarean section at greater risk of obesity: Harvard
Babies born by caesarean section are 15% more likely to become obese as children in comparison to those born naturally, and that increased risk could persist into adulthood, according to a new study by Harvard University, adding also that those born by C-section had a 64% greater chance of becoming obese compared with natural born siblings, despite growing up within the same environment. The use of C-sections to deliver babies is growing; in the UK 26% of births now involving the procedure, and in the US nearly 1.3 million C-sections are performed every year - accounting for one in three deliveries.

Babies delivered by Caesarean section are more likely to be obese children than those born naturally, new research suggests.

Experts at Harvard School of Public Health 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, the researchers found.

The use of C-sections to deliver babies is growing in Britain, with 26 per cent of births now involving the procedure.

Although in many cases the operation is necessary to avoid complications, doctors are increasingly aware it may have a knock-on impact on the child later in life.

Youngsters born via Caesarean delivery were 64 per cent more likely to be obese than their siblings born by vaginal birth (file photo)

Experts think this is mainly because babies removed directly from the womb are never 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 new study, published in the journal JAMA Paediatrics, tracked more than 22,000 people from birth.

The researchers examined the participants when they were aged between nine and 14, and found that those who had been born via C-section were 15 per cent more likely to be obese than those who underwent a natural birth.

They re-examined the participants again when they were aged between 20 and 28, and found that the impact persisted – although it had dropped to a 10 per cent difference.

The effect of C-section and natural births was even more stark within families, the researchers found.

Youngsters born via Caesarean delivery were 64 per cent more likely to be obese than their siblings born by vaginal birth.

Senior author Jorge Chavarro, associate professor of nutrition and epidemiology, said: ‘Caesarean deliveries are without a doubt a necessary and lifesaving procedure in many cases.

‘But Caesareans also have some known risks to the mother and the newborn. Our findings show that risk of obesity in the offspring could be another factor to consider.

Babies delivered by Caesarean section are more likely to be obese children, the study found

‘I think that our findings - particularly those that show a dramatic difference in obesity risk between those born via Caesarean and their siblings born through vaginal delivery - provide very compelling evidence that the association between Caesarean birth and childhood obesity is real.

‘That's because, in the case of siblings, many of the factors that could potentially be playing a role in obesity risk, including genetics, would be largely the same for each sibling - except for the type of delivery.’

Commenting on the study, Dr Daghni Rajasingam, of the Royal College of Obstetricians and Gynaecologists, said: ‘This is an interesting study which suggests that Caesarean birth may be associated with offspring obesity after accounting for other risk factors including maternal BMI, pre-pregnancy smoking habits and any pre-existing medical conditions such as gestational diabetes.

‘Currently in England, the rate of Caesarean section is 26.2 per cent, this figure has been rising slowly over the last decade and could be explained by various factors which make childbirth more difficult including; a rise in older mothers and more obese mothers.

‘We must remember that in some cases an emergency Caesarean section is carried out to save the life of the mother and/or baby.

‘Further research is needed to clarify the mechanisms underlying this possible association, but as with any intervention all doctors must ensure that women are informed about the risks and benefits of a Caesarean section, as well as the alternative options.’

Dr Simon Cork of Imperial College London, added: ‘Bacteria in the gut play a role in an ever increasing number of functions, including how much and what we eat, and the bacteria present in very early life are heavily influenced by how we’re delivered.