For expectant moms who may contemplate the pros and cons of
natural child birth or Caesarean section, a Henry Ford Hospital study suggests
that C-section babies are susceptible to developing allergies by age two.
Researchers found that babies born by C-section are five
times more likely to develop allergies than babies born naturally when exposed
to high levels of common allergens in the home such as those from dogs, cats
and dust mites.
Early exposure is key
"This further advances the hygiene hypothesis that early childhood
exposure to microorganisms affects the immune system's development and onset of
allergies," says Christine Cole Johnson, Ph.D., MPH, chair of Henry Ford
Department of Health Sciences and the study's lead author. "We believe a
baby's exposure to bacteria in the birth canal is a major influencer on their
Dr. Johnson says C-section babies have a pattern of "at
risk" microorganisms in their gastrointestinal tract that may make them
more susceptible to developing the antibody Immunoglobulin E, or IgE, when
exposed to allergens. IgE is linked to the development of allergies and asthma.
For its study Henry Ford researchers sought to evaluate the
role of early exposure to allergens and how this exposure affects the
association between C-section and the development of IgE.
Researchers enrolled 1,258 newborns from 2003-2007, and
evaluated them at four age intervals – one month, six months, one year and two
years. Data was collected from the baby's umbilical cord and stool, blood
samples from the baby's mother and father, breast milk and household dust, as
well as family history of allergy or asthma, pregnancy variables, household
pets, tobacco smoke exposure, baby illnesses and medication use.