Study Finds Causal Link Between C-section Birth and Increased Risk of Obesity


There is mounting evidence that the way in which you are born, and fed during early infancy may affect your health and predisposition to chronic diseases and metabolic conditions such as obesity, diabetes, asthma, allergies and IBD.

As incidences of Cesarean sections become more widely used, a correlation between their increased use and the rise of diseases such as allergies, celiac disease or obesity has alarmed many scientists.

Now a new study has shown for the first time a direct causal relationship between birth by cesarean section and increased body weight in mammals. The study set out to determine whether the initial microbiota that forms in a baby can affect its risk of becoming obese in the future.

The Cesarean-section is a necessary life-saving procedure for the mother or the child required in up to 15% of all childbirths according to the World Health Organisation (WHO). However, C-section births are increasingly chosen for convenience by patients and physicians in many parts of the world and the rates of delivery using this procedure have risen to as much as 25-45% in north America, Europe and Asia and as high as 50% in Latin America and the Middle East.

As part of the procedure it is normal for antibiotics to be given to prevent infection, with the resulting hypothesis that the combination of both the cesarean section and the antibiotics together affect the transmission of microbiota from the mother to the infant, which will in turn affects the development of the immune system and metabolism

The study– conducted at NYU School of Medicine – used two groups of laboratory mice – one group delivered by C-section without the use of antibiotics, and the second group delivered vaginally. The two groups of offspring were then kept in the same controlled environments and the two groups were monitored.

After 20 weeks the researchers found that the mice delivered by C-section were found to have increased in weight by 33% over the control group of mice delivered vaginally.

When the researchers examined the make up of the gut bacteria in the offspring composition after 8 weeks they found an unusual mixture of microorganisms, in the mice delivered by C-section lacking in Bacteroides, Ruminococcaceae, Lachnospiraceae and Clostridiales – all ‘good’ bacteria associated lean body types.

While the results are interesting, the results cannot be directly mapped to humans with a far more complex microbiome. It is also important to note that the role and duration of maternal breastfeeding in humans – which is also important in the colonisation and development of gut microbiota – was not investigated in this research.