Mode of Birth Is Not Associated With Food Allergy Risk in Infants

BACKGROUND: The association between mode of delivery and the risk of food allergy remains unclear due to the absence of studies with both challenge-proven food allergy outcomes and detailed information on the type of caesarean delivery. OBJECTIVE: We assessed whether emergency or elective caesarean, or caesarean delivery in the presence or absence of labor initiation, is associated with the risk of food allergy. METHODS: The HealthNuts study recruited 5276 12-month-old infants who underwent skin prick testing and oral food challenge to ascertain food allergy status, and linked the child's study data to additional birth data from the Victorian Perinatal Data Collection. RESULTS: Parents of 3006 children consented to data linkage, and birth data were obtained on 2045. In this subgroup, 30% were born by caesarean and 13% had food allergy. Caesarean delivery, compared with vaginal birth, was not associated with the risk of food allergy (adjusted odds ratio [aOR]: 0.95, 95% confidence interval [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 no evidence of effect modification by breastfeeding, older siblings, pet dog ownership, or maternal allergy. CONCLUSION: Caesarean delivery, either with or without labor, or elective or emergency, was not associated with the risk of food allergy in a population-based cohort of 12-month-old infants. (C) 2022 American Academy of Allergy, Asthma & Immunology