Mode of birth is not associated with food allergy risk in infants
Published: May 18, 2022
The microbial exposure hypothesis proposes that a lack of exposure to a variety of microbes and infections in early life can influence the development of the immune system, predisposing infants to allergic disease. Studies have shown that children with food allergy present with altered gut microbial composition compared to children without food allergy. Furthermore, variations in the gut microbial composition between infants born by a caesarean compared to vaginal delivery, have been observed. This suggests a plausible pathway by which mode of delivery can modify the risk of developing allergic disease.
Previous research on the association between mode of birth and risk of food allergy has produced mixed findings. This may be because previous studies did not have accurate food allergy outcomes using the gold-standard oral food challenge, nor detailed information on the type of caesarean delivery. Caesarean delivery, in the absence of labour may bypass the opportunity for neonatal gut colonization with maternal gut and vaginal flora. In a recent issue of The Journal of Allergy and Clinical Immunology: In Practice, Currell et al report results from the Australian HealthNuts study, which linked challenge-confirmed food allergy outcomes, to detailed information on birth factors collected routinely in hospitals.
The HealthNuts study recruited 5276 12-monthold infants who underwent skin prick testing and oral food challenge to ascertain food allergy status. At the 6-year-old follow-up, consent was sought to link the child’s study data to additional birth data from the Victorian Perinatal Data Collection. Parents of 3006 children consented to data linkage, and birth data were obtained on 2045. In this subgroup, 30% were born by caesarean. Caesarean delivery, compared with vaginal birth, was not associated with the risk of food allergy (aOR 0.95, 95% CI 0.70-1.30). Neither caesarean delivery before the onset of labor, nor after the onset of labor, was associated with the risk of food allergy (aOR: 0.83, 95% CI 0.55-1.23 and aOR: 1.13, 95% CI: 0.75-1.72, respectively). Delivery by elective or emergency caesarean, compared with vaginal delivery, was not associated with risk of food allergy (aOR: 1.05, 95% CI: 0.71-1.55 and aOR: 0.86, 95% CI:
0.56-1.31).
There was insufficient evidence that mode of delivery has a meaningful impact on the risk of developing food allergy in infants. These findings can assist caregivers in evaluating the risks and benefits of caesarean delivery and may provide reassurance for mothers who require such interventions that there is little evidence that their infants will be at an increased risk of food allergy after caesarean delivery.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.
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