Which term describes substances that can cause birth defects if exposure occurs during pregnancy?

• A. Embryology
• B. Teratology
• C. Teratogenicity
• D. Teratogens

Answer: (D)

Substances that can cause birth defects if exposure occurs during pregnancy are called teratogens. This term names the agents themselves—such as certain medications, alcohol, or infectious substances—that can disrupt fetal development at sensitive times. Teratogenicity, on the other hand, describes the potential or capacity of a substance to cause birth defects, not the substances themselves. Teratology is the field that studies birth defects and their causes, while embryology is the broader study of embryo development. So the term that best fits the description is teratogens.