Prenatal Stress Enhances Susceptibility to Allergic Diseases of Offspring

Maternal prenatal stress (MPS) may result in a range of longterm consequences in the offspring among which there is susceptibility to allergic diseases. This review presents the current knowledge on the pathways through which MPS may affect the fetus, and the existing evidence regarding the association between MPS and development of allergy in the offspring.

A pivotal mediator triggered in response to stress is the release of glucocorticoids (GC). GC may affect gene expression through binding to GC receptors, thus affecting fetal development in general, and allergic vulnerability in particular. A series of recent findings also indicate that MPS may affect the fetus programming of immune functions and lead to vulnerability of the immune system. MPS may hinder the gradual process in the offspring's cytokine production towards a Th1 type immune response. Prenatal factors may also influence the intrauterine microbiome and thereby the maternal bacteria transferred into the fetal gastrointestinal tract. The imbalances of intestinal microbiota in infancy could result in deviations in the development of systemic immune function, predisposing to allergic sensitization. Epidemiological studies in humans also suggest that there is an association of MPS and allergic vulnerability of the offspring.

Although the existing evidence support a relationship of MPS with allergic predisposition of the offspring, further studies are needed to elucidate whether the association is dependent on the type of stress and whether it involves any type of allergic predisposition or not.