During development in the womb, there are specific time periods in which particular organs and bodily systems develop. These critical periods of development can be affected by exposures to toxic stress, poor nutrition or environmental pollutants. The length and timing of these stressors on the developing baby can impact how organs and systems will develop. These stressors will also affect the long-term chronic disease risk of that fetus later in his or her life.
“Trading-off” is a protective process that ensures the survival of the developing fetus. Trade-offs occur when limited nutritional resources are allocated for developing critical organs like the brain and heart, at the expense of others, such as the pancreas or kidneys. This sort of trade-off is a survival mechanism that has consequences later in life for that developing fetus. Additionally, the post-birth environment is going to be vastly different than the uterine environment. So if a developing fetus made developmental trade-offs that affected the pancreas, for example, its sensitivity to insulin is diminished, which increases the risk for type 2 diabetes later in life.
Armitage, J. A., Taylor, P. D., & Poston, L. (2005). Experimental models of developmental programming: Consequences of exposure to an energy rich diet during development. The Journal of Physiology,565(1), 3-8.