Environmental Factors

There have been numerous changes in our way of life over the past 3 to 4 decades. Many of them, in turn, have changed the environment of a developing fetus. Pregnant women are more likely to be older, work at a career, travel great distances, eat food that they have not prepared themselves, take medications, and in general are under more stress than their mothers or grandmothers. There are numerous environmental changes to consider when studying the pregnancy environment today. It may be that there is a threshold of tolerance to environmental factors, above which our genes cannot compensate, where brain development becomes abnormal.

Environmental influences on the physiology of a developing fetus can stem from exposures the mother may encounter (exogenous) or can result from changes within the mother (endogenous). In the case of an exogenous environmental influence, the mother’s exposure is transferred to the fetus. Exogenous environmental factors include certain viruses, medications, exposure to pesticides and heavy metals, as well as neurotoxins in the food supply and other factors. Endogenous environmental influences may result from the subsequent effects that stress can cause in the mother and in the mother’s womb. They can also stem from factors such as the mother’s immune response to infections or foreign proteins or even her immune response to the father’s protein, which is expressed in the fetus she is carrying. Other endogenous environmental changes may occur in the mother’s womb as a result of the use of an Assisted Reproductive Therapy (ART), such as In Vitro Fertilization (IVF).