More than 1,293,000 children were born by cesarean section in 2011, according to the Centers for Disease Control and Prevention, which means nearly one-third of all babies are born by C-section. Originally developed to save lives, there is now evidence to suggest C-sections may cause allergies later in life. A new study suggests that children born by cesarean section are five times more likely to develop allergies when exposed to household allergens like dust mites and pet dander than are those born naturally.

Researchers from the Henry Ford Hospital presented their findings at the American Academy of Allergy, Asthma, and Immunology yearly meeting in San Antonio. These scientists believe that early childhood exposure to microorganisms positively affects the immune system and reduces the risk for allergies. The study’s lead author and chair of the Henry Ford Department of Health Sciences Christine Cole Johnson, Ph.D., MPH, says that the research team believes “a baby’s exposure to bacteria in the birth canal is a major influencer on their immune system.”

Dr. Johnson says that babies born by C-section have a pattern of microorganisms in their digestive tracts that make these babies more susceptible to the antibody Immunoglobulin E (IgE) when exposed to allergens. Allergy specialists link IgE to the development of allergies and asthma.

The team of researchers studied 1,258 newborns from 2003-2007. The scientists evaluated these children at the ages of one month, six months, one year, and two years. Researchers collected data from the baby’s umbilical cord and stool, blood samples from the mother and father, breast milk, and measured household dust, along with gathering the family history of allergy or asthma, household pets, exposure to tobacco smoke, illnesses during infancy, and medication use.

Women should talk with their doctors to discuss all the options when it comes to delivering a baby. A woman may not always be able to choose a vaginal delivery, as cesarean sections are often a medically necessary procedure.


  • Glynn, Sarah. "C-Section Babies 5 Times More Likely To Develop Allergies." Medical News Today. MediLexicon, Intl., 27 Feb. 2013. Web. 14 Aug. 2013.
  •       University, Linköping. "Children born by Caesarean section at greater risk for allergies." Medical News Today. MediLexicon, Intl., 12 Aug. 2013. Web.
    14 Aug. 2013.
  • Henry Ford Health System. Study: Babies Born by C-section at Risk of Developing Allergies. Feb 24, 3013.