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Cutting to the Chase: C-Sections & Allergies

Both of my children where born via Cesarean Section.  One emergency, one planned, and both with severe food allergies.  Interestingly, there is data to suggest that how they were delivered may have played a role in how they respond to foods. 


Research studies have found a significant connection between C-section births and food allergies.  Children born by C-section have a 3-fold higher probability of food allergies and having at least one allergic parent increases this to a 10-fold higher probability [1].


There are a few theories behind this connection:

Gut Microbiome


Allergic and non-allergic children have different intestinal bugs.  Early colonization by microflora from the mother’s birth canal may protect against the development of allergic diseases.  Exposure to maternal bacteria during natural birth allows for a population of good bugs that has a protective effect against allergies.  This is due to the proteins secreted by the bacteria.  C-sections decrease variety of bug species which are necessary for these defensive proteins to be created which may cause a food sensitivity [2]. 


Essentially, infants born vaginally will acquire their microbiome from the maternal vaginal and fecal flora as well as the environment.  A C-section is administered in a sterile operating room where very few, if any, of this microbe population is introduced to the baby.  Additionally, mothers typically receive antibiotic treatment prior to delivery which could affect bacterial growth in the child.  These factors cause a gut colonization delay in C-section babies and long-term significant differences in bacterial populations [3].


Immune Response

C-sections are shown to affect immune system maturation due to different birth stress levels.  During vaginal delivery, contractions and fetal responses cause an increase in cortisol which promotes immune system maturation [4].  In addition to altered cortisol levels, the timing between vaginal and C-section delivery is vastly changed.  Vaginal births allow for a slow increase in stress leading up to birth (gradual progression of contractions) while C-section babies typically experience an immediate stress.  Different timing could also contribute to a dysfunctional immune system which includes a significantly lower number of immune cells [5].    


Maternal Age

Maternal age may also be a contributing factor to food allergy risk-factors.  One study showed that mothers of food allergic children had approximately three times higher odds of being 30+ years old at time of delivery [6].  Since C-section deliveries are more common for mothers over 30 the question then becomes which issue may be at fault: age, delivery method, neither, both?




This is meant to shine a light on how delivery may affect food allergies, not to shame anyone for their birth story.  The more we know, the better we can identify how to help C-section babies and someday have options to account for the differences.  As with most studies, this is a correlation of many mothers and their infants.  There will always be outliers. 

Breastfeeding can help!  Breast milk provides baby with good bacteria from the milk itself as well as from mother’s skin.  If possible, try to breastfeed as quickly as possible after any type of birth.


  1. Papathoma E, Triga M, Fouzas S, Dimitriou G. Cesarean section delivery and development of food allergy and atopic dermatitis in early childhood. Pediatric Allergy and Immunology. 2016 Jun;27(4):419-24.

  2. Sjögren YM, Jenmalm MC, Böttcher MF, Björkstén B, Sverremark‐Ekström E. Altered early infant gut microbiota in children developing allergy up to 5 years of age. Clinical & Experimental Allergy. 2009 Apr;39(4):518-26.

  3. Grölund MM, Lehtonen OP, Eerola E, Kero P. Fecal microflora in healthy infants born by different methods of delivery: permanent changes in intestinal flora after cesarean delivery. Journal of pediatric gastroenterology and nutrition. 1999 Jan 1;28(1):19-25.

  4. Sevelsted A, Stokholm J, Bønnelykke K, Bisgaard H. Cesarean section and chronic immune disorders. Pediatrics. 2015 Jan 1;135(1):e92-8.

  5. Hyde MJ, Mostyn A, Modi N, Kemp PR. The health implications of birth by Caesarean section. Biological Reviews. 2012 Feb;87(1):229-43.

  6. Zasloff E, Schytt E, Waldenström U. First time mothers’ pregnancy and birth experiences varying by age. Acta obstetricia et gynecologica Scandinavica. 2007 Jan 1;86(11):1328-36.