Elective c-section linked to overweight risk

Elective c-section linked to overweight risk

A new study has found that babies born by elective - but not emergency - caesarean were more likely to be overweight at 12 months age.

And researchers say that this makes it even more important that health professionals discuss delivery choices and their possible long-term implications with expectant parents.

Globally, caesarean rates have more than doubled over the past two decades, with a rising proportion of them elective caesareans (performed before the mother goes into labour).

Emergency caesareans are performed due to medical complications that arise during labour.
Caesarean delivery has been linked to overweight and obesity in early childhood, but the reasons for this link are not yet clear.

The new study, published in JAMA Network Open today, draws on data from the ongoing Growing Up in Singapore Towards Health Outcomes (GUSTO) study. The international research team, which includes renowned child obesity expert Professor Sir Peter Gluckman from the University of Auckland-based Liggins Institute, analysed data from 727 babies and their mothers from GUSTO. Almost a third (222) of the babies were born via caesarean, of which a third (74) were elective.

Researchers compared the body mass index-for-age measures at 12 months of age in babies born by elective and emergency caesarean against babies born vaginally. Of the babies born by elective caesarean, 24.3 percent were at risk of overweight or overweight, compared to 14.9 percent of the emergency caesarean-born babies and 13.1 percent of the vaginally born babies.

The link remained when other possible reasons for this raised risk were factored in: the mother’s ethnicity, age, education, body mass index, smoking, high blood pressure, gestational diabetes.

This study is one of the first to tease out the effects of elective versus emergency caesareans.

Says Professor Gluckman: “The most likely explanation for the difference in babies’ overweight susceptibility is that babies born by elective caesarean are not exposed to their mothers’ bacteria as would normally occur during labour, and nor do they undergo the stress of labour.
Other evidence suggests these two factors – maternal bacteria and a surge in hormones such as cortisol in the baby due to the stress of labour – help set babies on a developmental pathway to healthy weight in childhood.

“Babies born by emergency caesarean generally have already experienced some labour, and the membrane surrounding them in the womb has been ruptured, allowing mothers’ bacteria in.”

The researchers say that if further research bears out the link to overweight risk, health professionals should consider discussing the potential long-term effects of elective caesareans on children. Past studies have found links to raised levels of other conditions later in life, such as type 1 diabetes and asthma.

Professor Gluckman: “This study waves a red flag: the rising epidemic of elective caesareans – a social trend rather than a health trend – is not without some potential costs for the baby. On the other hand, when a caesarean is indicated for medical reasons there should be absolutely no hesitation, as in those circumstances it is best for mother and baby.”

The study was led by researchers from the Duke-NUS Medical School in Singapore.

Related study:
JAMA Network Open: Association of Elective and Emergency Cesarean Delivery With Early Childhood Overweight at 12 Months of Age

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