Teratogens

Teratogens are substances or environmental factors that can cause congenital abnormalities or increase the incidence of a birth defect in a developing fetus. The term originates from the Greek words "teras" meaning monster and "genes" meaning born of, produced by. Teratogens can have a variety of harmful effects, depending on when during the pregnancy they are introduced.

Types of Teratogens

There are several types of teratogens including drugs, chemicals, infections, radiation, and malnutrition.

• Drugs such as thalidomide, alcohol, and certain anticonvulsants can have teratogenic effects.
• Chemicals like lead, mercury, and polychlorinated biphenyls (PCBs) can also be teratogenic.
• Certain infections during pregnancy can cause birth defects, including rubella, cytomegalovirus, and Zika virus.
• Radiation including X-rays and radioactive isotopes can be teratogenic.
• Malnutrition and certain vitamin deficiencies can also have teratogenic effects.

Effects of Teratogens

The effects of teratogens on a developing fetus can vary greatly depending on the type of teratogen, the duration of exposure, and the stage of fetal development at the time of exposure. Teratogens can cause a wide range of birth defects, from minor anatomical abnormalities to severe mental retardation or death.

Prevention

Prevention of teratogenic effects primarily involves avoiding exposure to known teratogens during pregnancy, including certain medications, alcohol, illicit drugs, and environmental toxins. Adequate nutrition and immunization against certain infectious diseases can also help prevent teratogenic effects.

See Also

• Congenital abnormalities
• Fetal alcohol syndrome
• Thalidomide disaster
• Zika virus