C-section babies are five times more likely to develop allergies by age two than those born naturally.

The finding came from a new study conducted by researchers from Henry Ford Hospital and was presented at the American Academy of Allergy, Asthma, and Immunology yearly meeting in San Antonio.

The findings coincide with previous research which demonstrated that babies born by c-section are more likely to have asthma than babies delivered naturally.

A different report showed that caesarean section babies have an increased risk of food allergies and diarrhea during their first year of life.

The new report indicated that c-section (cesarean section) babies are more vulnerable to allergies. They found that the chance of developing allergies for c-section babies is five times greater than for those born naturally when exposed to high levels of common allergens in the home, including those from cats, dogs, and dust mites.

Leading author Christine Cole Johnson, Ph.D., MPH, chair of Henry Ford Department of Health Sciences, said:

"This further advances the hygiene hypothesis that early childhood exposure to microorganisms affects the immune system's development and onset of allergies. We believe a baby's exposure to bacteria in the birth canal is a major influencer on their immune system."

In the gastrointestinal tract of babies born by c-section, there is a pattern of "at risk" microorganisms that may cause them to be more vulnerable to developing the antibody Immunoglobulin E, or IgE, when in contact with allergens, according to Dr. Johnson.

It is known that IgE is associated with the development of asthma and allergies.

For the purpose of the study, the experts at Henry Ford set out to assess the role of early exposure to allergens and analyze how this exposure has an impact on the link between c-section and the development of IgE.

A total of 1,258 newborns were involved in the investigation from 2003 until 2007 and were assessed at 4 different times: at one month old, six months, one year, and two years.

The researchers gathered data from:
  • the baby's umbilical cord and stool
  • breast milk
  • household dust
  • blood samples from the baby's mother and father
  • family history of allergy or asthma
  • household pets
  • tobacco smoke exposure
  • medication use
  • baby illnesses
  • pregnancy variables
The research received funding from Henry Ford Hospital and National Institute of Allergy and Infectious Diseases.

Written by Sarah Glynn