teratojen

Teratogens are agents that disrupt normal embryonic or fetal development, potentially causing birth defects, growth restriction, or neurodevelopmental disorders. They can be chemical substances, physical factors such as radiation, infectious agents, or certain environmental exposures. The risk depends on the dose, timing during pregnancy, duration of exposure, and the fetus’s genetic susceptibility, as well as interactions with other exposures. The most sensitive period for major structural anomalies is organogenesis, roughly the first eight weeks of gestation, but exposure at other times can lead to functional deficits or growth impairment and, in some cases, pregnancy loss.

Common teratogens include alcohol, certain prescription medicines such as retinoids, some anticonvulsants, and other drugs with known fetal risk, tobacco, and illicit drugs. Infections such as rubella, toxoplasmosis, cytomegalovirus, and Zika virus, as well as ionizing radiation and certain heavy metals, can also cause fetal damage. The spectrum of effects ranges from specific malformations to neurodevelopmental disorders and subtle cognitive or behavioral problems that may become apparent only after birth.

Prevention relies on preconception care, appropriate vaccination, avoidance or careful use of known teratogens, and, where applicable, therapeutic risk assessment and monitoring. Folic acid supplementation reduces neural tube defects; regulated access programs exist for some high-risk medications, and drug labeling and regulatory guidance emphasize risk communications to support informed decisions during pregnancy. Ongoing research aims to identify additional teratogens and clarify mechanisms of embryonic vulnerability.