Previously, several studies have shown immunological differences between children with and without allergy at the time of birth. Scientists now believe they may have identified a biological explanation for the link between cesarean-section delivery and risk of allergy and asthma in childhood.

From research carried out at the University of California, it appears the stress and process of labor itself may positively influence neonatal immune responses. While these findings are preliminary and further work is needed to explore potential mechanisms for the association between mode of delivery and neonatal immune responses, they do indicate a potential immunologic basis for previous reports of the relationship between cesarean section delivery and childhood allergy.