Babies born by Caesarean section may be at greater risk of diarrhoea

Babies born by Caesarean section may be at greater risk of diarrhoea and sensitisation to certain foodstuffs during their first 12 months than babies born vaginally, suggests research in the Archives of Disease in Childhood.

The findings are based on 865 babies, who were not premature and had been exclusively breast fed until they were four months old. They were all born into families with a history of allergies and were being monitored as part of the German Infant Nurtitional Intervention Program (GINI) study.

The babies were monitored at one, four, eight and 12 months of age. Blood samples were also taken after 12 months to check for antibodies to food allergens, including eggs, cows' milk proteins, and soy protein. And during the first six months, their mothers completed weekly diaries on their children's health and feeding.

In all, 147 of the 865 babies had been born by C-section, a rate of 17%. Pregnancy risk factors and maternal illnesses were no different between babies born by C-section and those born vaginally. But delivery by C-section was four times as likely among mothers who had already done this for previous births. Poor fetal positioning was also more likely among those delivering by C-section.

Neither colicky pain nor atopic dermatitis during the first four months of life were associated with type of delivery. But babies born by C-section were significantly more likely to have diarrhoea up to the age of 12 months.

They were also twice as likely as babies born vaginally to be sensitised to cows' milk and any of the five food allergens at 12 months of age.

The authors suggest that their findings are in keeping with other research indicating the importance of gut bacteria in the development of the immune system response, and that C-section alters or delays "normal" bacterial colonisation of the baby's gut.

They suggest that vaginally delivered babies acquire the mother's vaginal, intestinal, and perianal bacteria, whereas babies born by C-section acquire bacteria from the hospital environment.