A C-section (cesarean section) is a surgical procedure used to deliver a baby. It is often performed when a vaginal delivery would put the baby or mother at risk. The procedure is carried out in an operating theater under anesthetic, usually an epidural. In certain cases, C-section deliveries can be carried out under general anesthetic.

An extensive study, conducted in the USA and published in Jama Pediatrics, found that children born by cesarean section were 15% more likely to become obese than those delivered vaginally.

The researchers identified a link between birth by C-section and obesity risk. A sibling born by cesarean was 64% more likely to become obese than a brother or sister with the same parents delivered normally.

The scientists studied participants’ body mass index (BMI) over time, how they were born (C-section or vaginally) and other factors that could play a role in obesity, like their mothers’ BMI before pregnancy, smoking status, age at delivery and where they lived. They also looked at whether the participants’ mothers had previous C-section deliveries.

They found that individuals born by C-section were 15% more likely to become obese than those delivered vaginally. The study also suggests that this increased risk may persist through adulthood.

Children of women who gave birth vaginally after previous C-section deliveries were 31% less likely to become obese compared with those born via C-section following a previous C-section birth.

C-section deliveries can be recommended in cases of obstructed labour, multiple births, high blood pressure in the mother, breech birth, problems with the placenta, umbilical cord or shape of the pelvis, and previous C-section.

Ultrasound scans and prenatal examinations can help identify cases in which C-section delivery may be preferable.  Some C-sections are also performed upon request.