Babies born by Caesarean section are more likely to be obese than those delivered naturally, according to new research.
The study found that those born by C-section are 15% more likely to be obese in childhood.
That increased risk could persist through adulthood, according to researchers at the Harvard TH Chan School of Public Health.
Reseachers examined 16 years of data from more than 22,000 young adults in the study, published in the journal Jama Paediatrics.
It found that youngsters born by Caesarean were 64% more likely to be obese than siblings born by vaginal birth.
Around one in every four to five pregnant women in the UK has a Caesarean section.
Jorge Chavarro, an author on the study, 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.”
Dr Daghni Rajasingam, of the Royal College of Obstetricians and Gynaecologists, said the study should be interpreted cautiously.
She said it did not include data on why a Caesarean section was required or other details surround the labour or delivery.
“Currently in England, the rate of Caesarean section is 26.2%,” she said.
“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.”