Final answer:
Teratogenic drugs, which include a variety of prescription medications, illicit drugs, and other harmful substances, should be avoided by pregnant women to prevent birth defects or developmental issues in the fetus.
Step-by-step explanation:
Teratogenic drugs should be avoided in pregnant women because they can cause harm to the developing embryo or fetus. Teratogens are environmental agents which can be biological, chemical, or physical, like alcohol, drugs, and certain medications, that can result in birth defects or developmental issues. The use of these substances during pregnancy has been found to be a leading preventable cause of intellectual disabilities in children, as they can cross the placenta and affect fetal development.
Examples include heroin, cocaine, methamphetamine, prescription medications, over-the-counter medications, and other substances like radiation and some viruses. Thalidomide is a well-documented teratogen that caused deformities during embryogenesis. The effect of a teratogen on fetal development can depend on factors such as potency as a mutagen, the susceptibility of the fetus, and the dose of the teratogen.