teratogenne

Teratogenne are agents or factors that can cause congenital abnormalities or disrupt fetal development when a pregnant person is exposed, typically during early gestation when organ systems are forming. The term is used in several languages as the plural of teratogen, referring to substances or conditions with potential teratogenic effects.

Critical periods and outcomes vary. The most sensitive window is organogenesis, roughly weeks 3 to 8 of human gestation, though later exposures can impair growth or function. The outcome depends on dose, timing, and the fetus’s genetic susceptibility. Common teratogens include certain medications (such as thalidomide, isotretinoin, valproate and other anticonvulsants), some antibiotics, alcohol, illegal or recreational drugs, infectious agents (rubella, cytomegalovirus), and environmental toxins (lead, mercury).

Mechanisms of teratogenicity are diverse. They can involve interference with cell division or differentiation, disruption of signaling pathways, induction of apoptosis, DNA damage, folate antagonism, oxidative stress, or impairment of placental function. Some agents act indirectly by causing maternal illness, fever, or poor nutrition, which in turn affect fetal development.

Prevention focuses on reducing exposure during pregnancy and preconception planning. This includes avoidance of known teratogens when possible, vaccination against infections that harm the fetus, folic acid supplementation to reduce neural tube defects, and careful risk assessment of medications. Regulatory frameworks emphasize clear labeling and counseling to minimize fetal risk, reflecting historical lessons from past teratogenic outbreaks and tragedies. Teratology, the science of birth defects and abnormal development, continues to study how timing, dose, and genetics shape teratogenic risk.