organogènes

Organogens are the substances or agents that can cause birth defects, also known as congenital malformations, when exposure occurs during critical periods of fetal development. These agents are also referred to as teratogens. The term "organogen" specifically highlights the role of these agents in disrupting the normal formation of organs during embryogenesis and organogenesis. The critical period for teratogenic effects varies depending on the specific agent and the organ system being considered. For instance, the development of the central nervous system is sensitive to a wide range of insults throughout much of pregnancy, while the development of limbs has a more defined period of vulnerability.

The mechanisms by which organogens exert their harmful effects are diverse and can include direct damage to embryonic cells, interference with cell division, migration, or differentiation, or disruption of essential biochemical processes. Environmental factors, certain medications, infections, and maternal health conditions can all act as organogens. Examples include certain prescription drugs like thalidomide and isotretinoin, viral infections such as rubella, and exposure to high levels of radiation or certain industrial chemicals. The severity of the resulting birth defect depends on the dose, timing, and duration of exposure, as well as the genetic susceptibility of the developing fetus. Understanding organogens is crucial for preventative measures in prenatal care, guiding drug use during pregnancy, and identifying environmental risks.