Babies born by Caesarean section are no more likely to become obese in later life than those born naturally, a study suggests.


Instead, researchers say a child’s risk of obesity depends on the mother’s pre-pregnancy weight along with other factors such as genetics and environment.

The team from Sweden believe their findings, published in the journal PLOS Medicine, debunk the notion that being born by the surgical procedure increases risk of obesity in later life.

Dr Daniel Berglind, a researcher at the Karolinska Institutet and one of the study authors, said: “We found no evidence to support a link between C-sections and the development of obesity. This tells us that how women give birth may not be an important factor in the origins of the global obesity epidemic.”

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One in four UK babies is now delivered by C-section, according to recent figures published in the Lancet. Globally, the use of C-section has almost doubled since 2000, from 12 per cent in 2000 to 21 per cent in 2015.

The study used a population database of 97,291 male babies born between 1982 and 1987 in Sweden. Maternal and infant data was obtained from the country’s medical birth registry.

Weight and height measures, which were used to calculate the body-mass index (BMI) of the test subjects when they turned 18, were gathered from conscription examinations – part of the country’s mandatory requirement for enlistment in the armed forces.

The researchers said they were unable to collect information on female populations as, historically, men have been the ones to be drafted for military service.

Dr Viktor H Ahlqvist, also a researcher at the Karolinska Institutet and lead author, said: “As we only study males, our conclusion may only apply to a male population.

“However, previous studies have not observed any difference between males and females in the association between C-section and obesity, which suggest that there is no difference between males and females.”

Analysis revealed 5.5 per cent and 5.6 per cent of the men delivered through elective and emergency C-section, respectively, were obese compared to 4.9 per cent of the men who were born naturally.

But the researchers stress this connection between mode of delivery and obesity was more likely to be related to the mother’s weight along with family history of the condition.

Dr Ahlqvist said: “Most of the association between C-section and obesity could be explained by maternal pre-pregnancy BMI. This suggests that heritability and foetal exposure to obese-causing factors in the womb are more important when assessing the risk of obesity in the offspring than the mode of delivery.”

Commenting on the research, Pat O’Brien, a consultant obstetrician for the Royal College of Obstetricians and Gynaecologists, said: “We welcome the findings from this large scale study which offers reassurance to women who have had, or are preparing for, a Caesarean birth, that this procedure is not associated with obesity in their baby.

“This review counters findings from previous small studies that suggested a possible association between Caesarean birth and obesity.

“However, those previous studies did not consider other relevant factors including pre-pregnancy BMI, maternal and gestational age and the presence of diabetes, which all can affect the birth weight of a baby and the chances of having a Caesarean.

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“A Caesarean birth can be lifesaving to both mother and baby in emergency situations, and if a woman chooses to have a Caesarean birth, she should be supported in her decision.”


Sara RigbyOnline staff writer, BBC Science Focus

Sara is the online staff writer at BBC Science Focus. She has an MPhys in mathematical physics and loves all things space, dinosaurs and dogs.