The gut of a healthy fetus is sterile; after delivery the mother’s gut flora colonises the infant’s gut.
Infants at higher risk of atopic eczema, with the aim of preventing or reducing its incidence.
Higher risk is determined by a family history of allergic disease. There is a strong hereditary component to infant atopic eczema: if both parents have a history of eczema, the offspring risk is 60–80%.
Probiotics may reduce the relative incidence of atopic eczema by almost 80%. In trials, the favourable effect was similar across different periods of probiotic use (ie after delivery only or also during pregnancy), the receiver(s) of the probiotics (mother, child or both) and the duration of probiotic use.
Probiotics have several actions in the gut, including actively competing with pathogens for nutrition, making gut contents acidic, secreting local antimicrobial agents and enhancing specific and non-specific immune responses. The composition of gut flora may reduce allergies by driving maturation of the immune system.