Figure 3.

Of opportunities missed and taken. Early life microbial exposures influence developmental imprinting of the immune system that determines health and disease susceptibility in later life. Favorable imprinting of developing immunity by microbes may occur during an early life time window of opportunity. This window of opportunity, by definition, is predicted to be relatively short, to not arise again in later life and must provide a health benefit to the offspring. Numerous factors during pregnancy and in the postnatal period influence the quality of microbial exposures that have the potential to imprint immune functionality. Treatments and behaviors that disrupt these exposures may lead to pathological imprinting, altering risk for disease throughout life.