Caesarian birth greatly increases a baby’s chances of developing allergies, research has shown.
Babies delivered by C-section are five times more likely than those born ‘naturally’ to become allergic to triggers such as dust mites and pets, said Dr Christine Cole Johnson, from the Henry Ford Hospital, Detroit, US.
Babies could be left vulnerable by avoiding bacteria on the journey through the birth canal, the study found.
‘This further advances the hygiene hypothesis that early childhood exposure to micro-organisms affects the immune system’s development and onset of allergies,’ Dr Johnson said.
‘We believe a baby’s exposure to bacteria in the birth canal is a major influencer on their immune system.’
Dr Johnson’s team studied 1,258 newborn babies and assessed them when they were one month, six months, one year and two years old.
By two years of age, babies born by C-section were much more likely to have developed allergies to triggers in the home such as the droppings of house dust mites, and dander, or dead skin, shed by dogs and cats.
An estimated 21 million UK adults have at least one allergy. Ten per cent of children and adults under the age of 45 have two or more allergies.
Maureen Jenkins, director of clinical services at the charity Allergy UK, said: ‘During a natural birth the baby travels slowly down the birth canal where it ingests normal bacteria, which has been shown to aid a healthy immune response and protect against allergy.
‘In the case of a Caesarian section, the baby has no contact with the birth canal. Instead it is immediately removed from a sterile environment, meaning the chances of developing allergy could be heightened.’