Developmental Effects and Teratogenesis

A variety of biochemical effects caused by xenobiotics may be responsible for teratogenesis. These include enzyme inhibition, interference with energy supply, deprivation of the fetus of vitamins and other essential substrates, and altered permeability of the placental membrane. 

Fetuses exposed to toxic substances in utero are especially vulnerable to the effects of toxicants resulting in retarded fetal growth, birth defects, and maladies such as diabetes and coronary artery disease after birth. Exposure occurs when a toxic substance passes through the placental barrier and enters the fetal bloodstream. Fetuses are vulnerable to toxicants because they have relatively ineffective detoxification enzyme systems and their developing organs are more subject to damage than are mature organs. 

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